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1.  An Intervention to Reduce HIV Risk Behavior of Substance-Using Men Who Have Sex with Men: A Two-Group Randomized Trial with a Nonrandomized Third Group 
PLoS Medicine  2010;7(8):e1000329.
In a randomized trial of a behavioral intervention among substance-using men who have sex with men, aimed at reducing sexual risk behavior, Mansergh and colleagues fail to find evidence of a reduction in risk from the intervention.
Background
Substance use during sex is associated with sexual risk behavior among men who have sex with men (MSM), and MSM continue to be the group at highest risk for incident HIV in the United States. The objective of this study is to test the efficacy of a group-based, cognitive-behavioral intervention to reduce risk behavior of substance-using MSM, compared to a randomized attention-control group and a nonrandomized standard HIV-testing group.
Methods and Findings
Participants (n = 1,686) were enrolled in Chicago, Los Angeles, New York City, and San Francisco and randomized to a cognitive-behavioral intervention or attention-control comparison. The nonrandomized group received standard HIV counseling and testing. Intervention group participants received six 2-h group sessions focused on reducing substance use and sexual risk behavior. Attention-control group participants received six 2-h group sessions of videos and discussion of MSM community issues unrelated to substance use, sexual risk, and HIV/AIDS. All three groups received HIV counseling and testing at baseline. The sample reported high-risk behavior during the past 3 mo prior to their baseline visit: 67% reported unprotected anal sex, and 77% reported substance use during their most recent anal sex encounter with a nonprimary partner. The three groups significantly (p<0.05) reduced risk behavior (e.g., unprotected anal sex reduced by 32% at 12-mo follow-up), but were not different (p>0.05) from each other at 3-, 6-, and 12-mo follow-up. Outcomes for the 2-arm comparisons were not significantly different at 12-mo follow-up (e.g., unprotected anal sex, odds ratio = 1.14, confidence interval = 0.86–1.51), nor at earlier time points. Similar results were found for each outcome variable in both 2- and 3-arm comparisons.
Conclusions
These results for reducing sexual risk behavior of substance-using MSM are consistent with results of intervention trials for other populations, which collectively suggest critical challenges for the field of HIV behavioral interventions. Several mechanisms may contribute to statistically indistinguishable reductions in risk outcomes by trial group. More explicit debate is needed in the behavioral intervention field about appropriate scientific designs and methods. As HIV prevention increasingly competes for behavior-change attention alongside other “chronic” diseases and mental health issues, new approaches may better resonate with at-risk groups.
Trial Registration
ClinicalTrials.gov NCT00153361
Please see later in the article for the Editors' Summary
Editors' Summary
Background
AIDS first emerged in the early 1980s among gay men living in the US. As the disease spread around the world, it became clear that AIDS also affects heterosexual men and women. Now, three decades on, more than 30 million people are infected with HIV, the virus that causes AIDS. HIV is most often spread by having unprotected sex with an infected partner and, globally, most sexual transmission of HIV now occurs during heterosexual sex. However, 5%–10% of all new HIV infections still occur in men who have sex with men (MSM, a term that encompasses gay, bisexual, transgendered, and heterosexual men who sometimes have sex with men) and, in several high-income countries, male-to-male sexual contact remains the most important HIV transmission route. In the US, for example, more than half of the approximately 50,000 people who become infected with HIV every year do so through male-to-male sexual contact.
Why Was This Study Done?
In countries where MSM are the group at highest risk of HIV infection, any intervention that reduces HIV transmission in MSM should have a major effect on the overall HIV infection rate. Among MSM, sexual behaviors that increase the risk of HIV infection (for example, not using a condom, having anal sex, having sex with a partner of unknown HIV status, and having sex with many partners) are associated with the use of alcohol and noninjection drugs (for example, inhaled amyl nitrite or poppers) during or shortly before sexual encounters. In this study (Project MIX), the researchers investigate whether a group-based behavioral intervention reduces sexual risk behavior in substance-using MSM.
What Did the Researchers Do and Find?
The researchers recruited substance-using MSM from four US cities who had had risky sex at least once in the past 6 months. Participants were randomized to a cognitive-behavioral intervention or to an attention-control group; a third, nonrandomized group of MSM formed a standard HIV counseling and testing only group. All the groups had HIV counseling and testing at the start of the study and completed a questionnaire about their substance use and sexual risk behavior during their most recent anal sex encounter. The cognitive-behavior group then received six weekly 2-hour group sessions focused on reducing substance use and sexual risk behavior by helping the men change their thinking (cognition) and behavior regarding sexual risk taking. The attention-control group received six group sessions about general MSM issues such as relationships, excluding discussion of substance use, and sexual risk behavior. The participants in both of these groups completed the questionnaire about their substance use and sexual risk behavior again at 3, 6, and 12 months after the group sessions; the participants in the standard HIV counseling and testing group completed the questionnaire again about 5 months after completing the first questionnaire (to control for the time taken by the other two groups to complete the intervention). At baseline, about 67% of the participants reported unprotected anal sex and 77% reported substance use during their most recent anal sex encounter with a nonprimary partner. At the 3-month follow-up, the incidence of sexual risk behavior had fallen to about 43% in all three groups; the incidence of substance use during sex had fallen to about 50%. Risk taking and substance use remained at these levels in the intervention and attention-control groups at the later follow-up time points.
What Do These Findings Mean?
These findings suggest that this cognitive-behavioral intervention is no better at reducing sexual risk taking among substance-using MSM than is an unrelated video-discussion group or standard HIV counseling and testing. One explanation for this negative result might be that brief counseling is especially effective with people who are ready for a change such as MSM willing to enroll in an intervention trial of this type. Alternatively, just being in the trial might have encouraged all the participants to self-report reduced risk behavior. Thus, alternative scientific designs and methods might be needed to find behavioral interventions that can effectively reduce HIV transmission among substance-using MSM and other people at high risk of HIV infection. Importantly, however, these findings raise the question of whether more extensive, multilevel interventions or broader lifestyle and positive health approaches (rather than single-level or single-subject behavioral interventions) might be needed to reduce sexual risk behavior among substance-using MSM.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000329.
Information is available from the US Department of Health and Human Services on HIV prevention programs, research, and policy
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on all aspects of HIV/AIDS, including information on HIV transmission and transmission in gay men and other MSM, on substance abuse and HIV/AIDS, and on safer sex
Information is available from Avert, an international AIDS nonprofit, on all aspects of HIV/AIDS, including information on HIV, AIDS, and men who have sex with men and on drink, drugs, and sex (in English and Spanish)
The US Centers for Disease Control and Prevention also have information for the public and for professionals about HIV/AIDS among men who have sex with men (in English and Spanish)
The US National Institute on Drug Abuse has information on HIV/AIDS and drug abuse, including a resource aimed at educating teenagers about the link between drug abuse and the spread of HIV in the US (in English and Spanish)
doi:10.1371/journal.pmed.1000329
PMCID: PMC2927550  PMID: 20811491
2.  Are HIV Epidemics among Men Who Have Sex with Men Emerging in the Middle East and North Africa?: A Systematic Review and Data Synthesis 
PLoS Medicine  2011;8(8):e1000444.
A systematic review by Laith Abu-Raddad and colleagues collates and analyzes the epidemiology of HIV among men who have sex with men in Middle Eastern and North African countries.
Background
Men who have sex with men (MSM) bear a disproportionately higher burden of HIV infection than the general population. MSM in the Middle East and North Africa (MENA) are a largely hidden population because of a prevailing stigma towards this type of sexual behavior, thereby limiting the ability to assess infection transmission patterns among them. It is widely perceived that data are virtually nonexistent on MSM and HIV in this region. The objective of this review was to delineate, for the first time, the evidence on the epidemiology of HIV among MSM in MENA.
Methods and Findings
This was a systematic review of all biological, behavioral, and other related data on HIV and MSM in MENA. Sources of data included PubMed (Medline), international organizations' reports and databases, country-level reports and databases including governmental and nongovernmental organization publications, and various other institutional documents. This review showed that onsiderable data are available on MSM and HIV in MENA. While HIV prevalence continues at low levels among different MSM groups, HIV epidemics appear to be emerging in at least few countries, with a prevalence reaching up to 28% among certain MSM groups. By 2008, the contribution of MSM transmission to the total HIV notified cases increased and exceeded 25% in several countries. The high levels of risk behavior (4–14 partners on average in the last six months among different MSM populations) and of biomarkers of risks (such as herpes simplex virus type 2 at 3%–54%), the overall low rate of consistent condom use (generally below 25%), the relative frequency of male sex work (20%–76%), and the substantial overlap with heterosexual risk behavior and injecting drug use suggest potential for further spread.
Conclusions
This systematic review and data synthesis indicate that HIV epidemics appear to be emerging among MSM in at least a few MENA countries and could already be in a concentrated state among several MSM groups. There is an urgent need to expand HIV surveillance and access to HIV testing, prevention, and treatment services in a rapidly narrowing window of opportunity to prevent the worst of HIV transmission among MSM in the Middle East and North Africa.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
AIDS first emerged in the early 1980s among gay men living in the US. But, as the disease rapidly spread, it became clear that AIDS also affects heterosexual men and women. Now three decades on, more than 30 million people are infected with HIV, the virus that causes AIDS. HIV is most often spread by having unprotected sex with an infected partner and, globally, most sexual transmission of HIV now occurs during heterosexual sex. However, 5%–10% of all new HIV infections still occur in men who have sex with men (MSM, a term that encompasses homosexual, bisexual, and transgender men, and heterosexual men who sometimes have sex with men). In some countries, male-to-male sexual contact remains the most important transmission route. Moreover, although the global prevalence of HIV infection (the proportion the world's population infected with HIV) has stabilized, the prevalence of HIV infection among MSM seems to be increasing in multiple countries and new and resurgent HIV epidemics among MSM populations are being frequently reported.
Why Was This Study Done?
In the US and the UK, the MSM population is visible and has helped to raise awareness about the risks of HIV transmission through male-to-male sexual contact. In many other countries, MSM are much less visible, fearing discrimination, stigmatization (being considered socially unacceptable) or arrest. In the Middle East and North Africa (MENA, a geographical region that encompasses countries that share historical, socio-cultural, linguistic and religious characteristics), MSM are the most hidden HIV risk group. Consequently, very little is known about HIV transmission patterns among MSM in MENA. Indeed, it is widely thought that there is virtually no information available on the epidemiology (causes, distribution, and control) of HIV among MSM in this region. In this systematic review and data synthesis, the researchers use predefined search criteria to identify all the published and unpublished data on the epidemiology of HIV among MSM in MENA and combine (synthesize) these data to produce a coherent picture of the HIV epidemic in this potentially key group of people for HIV transmission in this region.
What Did the Researchers Do and Find?
The researchers identified 26 articles and 51 other country-level reports and sources of data that included data on the prevalence of male-to-male sexual contact, HIV transmission, levels of high-risk behavior, and the extent of knowledge about HIV among MSM in MENA. The prevalence of HIV infection among MSM was low in most countries but high in others. For example, the infection rate in Pakistan was 27.6% among one MSM group. Importantly, there was some evidence of increasing HIV prevalence and emerging epidemics among MSM in the region. Thus, by 2008, MSM transmission was responsible for more than a quarter of notified cases of HIV in several countries. Worryingly, MSM were involved in several types of HIV-related high risk behavior. For example, they had, on average, between 4 and 14 sexual partners in the past six months, their rates of consistent condom use were generally below 25% and, in some countries, MSM frequently reported injecting drug use, another common mode of HIV transmission. In addition, 20%–75.5% of MSM exchanged sex for money and contact between MSM and female sex workers and other female sexual partners was often common. Finally, although the level of basic knowledge about HIV/AIDS was high, the level of comprehensive knowledge was limited with a high proportion of MSM perceiving their risk of contracting HIV as low.
What Do These Findings Mean?
These findings indicate that there is considerable and increasing data about HIV transmission and risk behavior among MSM in MENA. However, the quality of this evidence varies greatly. Little has been collected over time in individual populations and, because only the visible part of the MSM populations in many MENA countries has been sampled, these findings may not be representative of all MSM in this region. Nevertheless, these findings suggest that HIV epidemics are emerging among MSM in several MENA countries. Importantly, the high levels of risk behaviors practiced by many MSM in MENA mean that MSM could become the pivotal risk group for HIV transmission in this region in the next decade. There is, therefore, an urgent need to expand HIV surveillance and access to HIV testing, prevention and treatment services among MSM in this region to limit the size of the HIV epidemic.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000444.
Information about the status of the HIV epidemic in the Middle East and North Africa can be found in the World Bank/UNAIDS/WHO report Characterizing the HIV/AIDS epidemic in the Middle East and North Africa: Time for strategic action
Information about the global HIV epidemic among men who have sex with men can be found in the World Bank report The Global HIV Epidemics among Men Who Have Sex with Men
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on all aspects of HIV/AIDS, including information on HIV transmission and transmission in gay men and other MSM and on safer sex
Information is available from Avert, an international AIDS charity, on all aspects of HIV/AIDS, including information on HIV, AIDS and men who have sex with men and on HIV and AIDS prevention (in English and Spanish)
The US Centers for Disease Control and Prevention also have information about HIV/AIDS among men who have sex with men (in English and Spanish)
doi:10.1371/journal.pmed.1000444
PMCID: PMC3149074  PMID: 21829329
3.  Elevated Risk for HIV Infection among Men Who Have Sex with Men in Low- and Middle-Income Countries 2000–2006: A Systematic Review 
PLoS Medicine  2007;4(12):e339.
Background
Recent reports of high HIV infection rates among men who have sex with men (MSM) from Asia, Africa, Latin America, and the former Soviet Union (FSU) suggest high levels of HIV transmission among MSM in low- and middle-income countries. To investigate the global epidemic of HIV among MSM and the relationship of MSM outbreaks to general populations, we conducted a comprehensive review of HIV studies among MSM in low- and middle-income countries and performed a meta-analysis of reported MSM and reproductive-age adult HIV prevalence data.
Methods and Findings
A comprehensive review of the literature was conducted using systematic methodology. Data regarding HIV prevalence and total sample size was sequestered from each of the studies that met inclusion criteria and aggregate values for each country were calculated. Pooled odds ratio (OR) estimates were stratified by factors including HIV prevalence of the country, Joint United Nations Programme on HIV/AIDS (UNAIDS)–classified level of HIV epidemic, geographic region, and whether or not injection drug users (IDUs) played a significant role in given epidemic. Pooled ORs were stratified by prevalence level; very low-prevalence countries had an overall MSM OR of 58.4 (95% CI 56.3–60.6); low-prevalence countries, 14.4 (95% CI 13.8–14.9); and medium- to high-prevalence countries, 9.6 (95% CI 9.0–10.2). Significant differences in ORs for HIV infection among MSM in were seen when comparing low- and middle-income countries; low-income countries had an OR of 7.8 (95% CI 7.2–8.4), whereas middle-income countries had an OR of 23.4 (95% CI 22.8–24.0). Stratifying the pooled ORs by whether the country had a substantial component of IDU spread resulted in an OR of 12.8 (95% CI 12.3–13.4) in countries where IDU transmission was prevalent, and 24.4 (95% CI 23.7–25.2) where it was not. By region, the OR for MSM in the Americas was 33.3 (95% CI 32.3–34.2); 18.7 (95% CI 17.7–19.7) for Asia; 3.8 (95% CI 3.3–4.3) for Africa; and 1.3 (95% CI 1.1–1.6) for the low- and middle-income countries of Europe.
Conclusions
MSM have a markedly greater risk of being infected with HIV compared with general population samples from low- and middle-income countries in the Americas, Asia, and Africa. ORs for HIV infection in MSM are elevated across prevalence levels by country and decrease as general population prevalence increases, but remain 9-fold higher in medium–high prevalence settings. MSM from low- and middle-income countries are in urgent need of prevention and care, and appear to be both understudied and underserved.
From a systematic review, Chris Beyrer and colleagues conclude that men who have sex with men in the Americas, Asia, and Africa have a markedly greater risk of being HIV-infected than does the general population.
Editors' Summary
Background.
AIDS (acquired immunodeficiency syndrome) first emerged in the early 1980s among gay men living in New York and California. But, as the disease rapidly spread around the world, it became clear that AIDS also affected heterosexual men and women. Now, a quarter of a century later, 40 million people are infected with human immunodeficiency virus (HIV), the organism that causes AIDS. HIV is most often spread by having unprotected sex with an infected partner and in sub-Saharan Africa, the region most badly hit by HIV/AIDS, heterosexual transmission predominates. However, globally, 5%–10% of all HIV infections are thought to be in men who have sex with men (MSM, a term that encompasses gay, bisexual, transgendered, and heterosexual men who sometimes have sex with men), and in several high-income countries, including the US, male-to-male sexual contact remains the most important HIV transmission route.
Why Was This Study Done?
In the US, the MSM population is visible and there is considerable awareness about the risks of HIV transmission associated with sex between men. In many other countries, MSM are much less visible. They remain invisible because they fear discrimination, stigmatization (being considered socially unacceptable), or arrest—sex between men is illegal in 85 countries. Consequently, MSM are often under-represented in HIV surveillance systems and in prevention and care programs. If the AIDS epidemic is going to be halted, much more needs to be known about HIV prevalence (the proportion of the population that is infected) among MSM. In this study, the researchers have done a systematic review (a type of research where the results of existing studies are brought together) on published reports of HIV prevalence among MSM in low- and middle-income countries to get a better picture of the global epidemic of HIV in this population.
What Did the Researchers Do and Find?
The researchers found 83 published studies that reported HIV prevalence in 38 low- and middle-income countries in Asia, Africa, the Americas, and Eastern Europe. When the results were pooled—in what statisticians call a meta-analysis—MSM were found to have a 19.3-times greater chance of being infected with HIV than the general population. This is described as a pooled odds ratio (OR) of 19.3. The researchers also did several subgroup analyses where they asked whether factors such as injection drug use (another risk factor for HIV transmission), per capita income, geographical region, or the HIV prevalence in the general population were associated with differential risk (increase in odds) of HIV infection compared to the general population. They found, for example, that in countries where the prevalence of HIV in the general population was very low (less than 1 adult in 1,000 infected) the pooled OR for MSM compared to the general population was 58.4; where it was high (more than 1 adult in 20 infected), the pooled OR for MSM was 9.6.
What Do These Findings Mean?
These findings indicate that MSM living in low- to middle-income countries have a greater risk of HIV infection than the general populations of these countries. The subgroup analyses indicate that the high HIV prevalence among MSM is not limited to any one region or income level or to countries with any specific HIV prevalence or injection drug use level. Although the small number and design of the studies included in the meta-analysis may affect the numerical accuracy of these findings, the clear trend toward a higher HIV prevalence of among MSM suggests that HIV surveillance efforts should be expanded to include MSM in those countries where they are currently ignored. Efforts should also be made to include MSM in HIV prevention programs and to improve the efficacy of these programs by investigating the cultural, behavioral, social, and public policy factors that underlie the high HIV prevalence among MSM. By increasing surveillance, research, and prevention among MSM in low- to middle-income countries, it should be possible to curb HIV transmission in this marginalized population and reduce the global burden of HIV.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040339.
The International Lesbian and Gay Association provides a world legal map on legislation affecting lesbian, gay, bisexual, and transgendered people
The International Gay and Lesbian Human Rights Commission provides a page called Off the Map: How HIV/AIDS Programming is Failing Same-Sex Practicing People in Africa
The American Foundation for AIDS Research (amfAR) has launched their MSM initiative, which is focused on providing support to front-line community groups working on providing services and doing research focused on HIV among MSM in lower income-settings
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on all aspects of HIV/AIDS, including a list of organizations that provide information for gay men and MSM
Information is available from Avert, an international AIDS charity, on HIV, AIDS, and men who have sex with men
The US Centers for Disease Control and Prevention provides information on HIV/AIDS and on HIV/AIDS among men who have sex with men (in English and Spanish)
doi:10.1371/journal.pmed.0040339
PMCID: PMC2100144  PMID: 18052602
4.  Associations between Intimate Partner Violence and Health among Men Who Have Sex with Men: A Systematic Review and Meta-Analysis 
PLoS Medicine  2014;11(3):e1001609.
Ana Maria Buller and colleagues review 19 studies and estimate the associations between the experience and perpetration of intimate partner violence and various health conditions and sexual risk behaviors among men who have sex with men.
Please see later in the article for the Editors' Summary
Background
Intimate partner violence (IPV) among men who have sex with men (MSM) is a significant problem. Little is known about the association between IPV and health for MSM. We aimed to estimate the association between experience and perpetration of IPV, and various health conditions and sexual risk behaviours among MSM.
Methods and Findings
We searched 13 electronic databases up to 23 October 2013 to identify research studies reporting the odds of health conditions or sexual risk behaviours for MSM experiencing or perpetrating IPV. Nineteen studies with 13,797 participants were included in the review. Random effects meta-analyses were performed to estimate pooled odds ratios (ORs). Exposure to IPV as a victim was associated with increased odds of substance use (OR = 1.88, 95% CIOR 1.59–2.22, I2 = 46.9%, 95% CII2 0%–78%), being HIV positive (OR = 1.46, 95% CIOR 1.26–1.69, I2 = 0.0%, 95% CII2 0%–62%), reporting depressive symptoms (OR = 1.52, 95% CIOR 1.24–1.86, I2 = 9.9%, 95% CII2 0%–91%), and engagement in unprotected anal sex (OR = 1.72, 95% CIOR 1.44–2.05, I2 = 0.0%, 95% CII2 0%–68%). Perpetration of IPV was associated with increased odds of substance use (OR = 1.99, 95% CIOR 1.33–2.99, I2 = 73.1%). These results should be interpreted with caution because of methodological weaknesses such as the lack of validated tools to measure IPV in this population and the diversity of recall periods and key outcomes in the identified studies.
Conclusions
MSM who are victims of IPV are more likely to engage in substance use, suffer from depressive symptoms, be HIV positive, and engage in unprotected anal sex. MSM who perpetrate IPV are more likely to engage in substance use. Our results highlight the need for research into effective interventions to prevent IPV in MSM, as well as the importance of providing health care professionals with training in how to address issues of IPV among MSM and the need to raise awareness of local and national support services.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Intimate partner violence (IPV, also called domestic violence) is a common and widespread problem. Globally, nearly a third of women are affected by IPV at some time in their life, but the prevalence of IPV (the proportion of the population affected by IPV) varies widely between countries. In central sub-Saharan Africa, for example, nearly two-thirds of women experience IPV during their lifetime, whereas in East Asia only one-sixth of women are affected. IPV is defined as physical, sexual, or emotional harm that is perpetrated on an individual by a current or former partner or spouse. Physical violence includes hitting, kicking, and other types of physical force; sexual violence means forcing a partner to take part in a sex act when the partner does not consent; and emotional abuse includes threatening a partner by, for example, stalking them or preventing them from seeing their family. The adverse effects of IPV for women include physical injury, depression and suicidal behaviour, and sexual and reproductive health problems such as HIV infection and unwanted pregnancies.
Why Was This Study Done?
IPV affects men as well as women. Men can be subjected to IPV either by a female partner or by a male partner in the case of men who have sex with men (MSM, a term that encompasses homosexual, bisexual, and transgender men, and heterosexual men who sometimes have sex with men). Recent reviews suggest that the prevalence of IPV in same-sex couples is as high as the prevalence of IPV for women in opposite-sex relationships: reported lifetime prevalences of IPV in homosexual male relationships range between 15.4% and 51%. Little is known, however, about the adverse health effects of IPV on MSM. It is important to understand how IPV affects the health of MSM so that appropriate services and interventions can be provided to support MSM who experience IPV. In this systematic review (a study that identifies all the research on a given topic using predefined criteria) and meta-analysis (a study that combines the results of several studies using statistical methods), the researchers investigate the associations between the experience and perpetration of IPV and various health conditions and sexual risk behaviours among MSM.
What Did the Researchers Do and Find?
The researchers identified 19 studies that investigated associations between IPV and various health conditions or sexual risk behaviours (for example, unprotected anal sex, a risk factor for HIV infection) among MSM. The associations were expressed as odds ratios (ORs); an OR represents the odds (chances) that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. The researchers estimated pooled ORs from the data in the individual studies using meta-analysis. The pooled lifetime prevalence of experiencing any IPV (which was measured in six studies) was 48%. Exposure to IPV as a victim was associated with an increased risk of substance (alcohol or drug) use (OR = 1.88, data from nine studies), reporting depressive symptoms (OR = 1.52, data from three studies), being HIV positive (OR = 1.46, data from ten studies), and engagement in unprotected sex (OR = 1.72, data from eight studies). Perpetration of IPV was associated with an increased risk of substance abuse (OR = 1.99, data from six studies).
What Do These Findings Mean?
These findings suggest that MSM frequently experience IPV and that exposure to IPV is associated with several adverse health conditions and sexual risk behaviours. There were insufficient data to estimate the lifetime prevalence of IPV perpetration among MSM, but these findings also reveal an association between IPV perpetration and substance use. The accuracy of these findings is limited by heterogeneity (variability) between the studies included in the meta-analyses, by the design of these studies, and by the small number of studies. Despite these and other limitations, these findings highlight the need to undertake research to identify interventions to prevent IPV among MSM and to learn more about the health effects of IPV among MSM. They highlight the importance of health care professionals being aware that IPV is a problem for MSM and of training these professionals to assess MSM for IPV. Finally, these results highlight the need to improve the availability and effectiveness of support services to which health care professionals can refer MSM experiencing or perpetrating IPV.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001609.
The World Health Organization provides detailed information on intimate partner violence
The US Centers for Disease Control and Prevention provides information about IPV and a fact sheet on understanding IPV that includes links to further resources
The UK National Health Service Choices website has a webpage about domestic violence, which includes descriptions of personal experiences
The US National Domestic Violence Hotline provides confidential help and support to people experiencing IPV, including MSM; its website includes personal stories of IPV
The US Gay Men's Domestic Violence Project/GLBTQ Domestic Violence Project provides support and services to MSM experiencing IPV; its website includes some personal stories
The UK not-for-profit organization Respect runs two advice lines: the Men's Advice Line provides advice and support for men experiencing domestic violence and abuse and the Respect Phoneline provides advice for domestic violence perpetrators and for professionals who would like further information about services for those using violence/abuse in their intimate partner relationships
The UK not-for-profit organization ManKind Initiative also provides support for male victims of IPV
The UK not-for-profit organization Broken Rainbow UK provides help and support for lesbians and MSM experiencing IPV
MedlinePlus provides links to other resources about domestic violence (in English and Spanish)
The UK charity Galop gives advice and support to people who have experienced biphobia, homophobia, transphobia, sexual violence, or domestic abuse
doi:10.1371/journal.pmed.1001609
PMCID: PMC3942318  PMID: 24594975
5.  Psychosocial health problems increase risk for HIV among urban young men who have sex with men: Preliminary evidence of a syndemic in need of attention 
BACKGROUND
Young men who have sex with men (YMSM) experience disparities in HIV rates and potentially in mental health, substance abuse, and exposure to violence.
PURPOSE
We assessed the extent to which these psychosocial health problems had an additive effect on increasing HIV risk among YMSM.
METHODS
An urban sample of 310 ethnically-diverse YMSM reported on psychosocial health problems, sexual risk behaviors, and HIV status. A count of psychosocial health problems was calculated to test the additive relationship to HIV risk.
RESULTS
The prevalence of psychosocial health problems varied from 23% for regular binge drinking to 34% for experiencing partner violence. Rates of sexual risk behaviors were high and 14% of YMSM reported receiving a HIV+ test result. Psychosocial health problems co-occurred, as evidenced by significant bivariate odds ratios between 12 of the 15 associations tested. Number of psychosocial health problems significantly increased the odds of having multiple anal sex partners (OR = 1.24), unprotected anal sex (OR = 1.42), and an HIV positive status (OR 1.42), after controlling for demographic factors.
CONCLUSIONS
These data suggest the existence of co-occurring epidemics, or “syndemic,” of health problems among YMSM. Disparities exist not only in the prevalence of HIV among YMSM, but also in research to combat the epidemic within this vulnerable population. Future research is needed to identify risk and resiliency factors across the range of health disparities and develop interventions that address this syndemic.
doi:10.1080/08836610701495268
PMCID: PMC2219199  PMID: 17688395
6.  Episodic Sexual Transmission of HIV Revealed by Molecular Phylodynamics 
PLoS Medicine  2008;5(3):e50.
Background
The structure of sexual contact networks plays a key role in the epidemiology of sexually transmitted infections, and their reconstruction from interview data has provided valuable insights into the spread of infection. For HIV, the long period of infectivity has made the interpretation of contact networks more difficult, and major discrepancies have been observed between the contact network and the transmission network revealed by viral phylogenetics. The high rate of HIV evolution in principle allows for detailed reconstruction of links between virus from different individuals, but often sampling has been too sparse to describe the structure of the transmission network. The aim of this study was to analyze a high-density sample of an HIV-infected population using recently developed techniques in phylogenetics to infer the short-term dynamics of the epidemic among men who have sex with men (MSM).
Methods and Findings
Sequences of the protease and reverse transcriptase coding regions from 2,126 patients, predominantly MSM, from London were compared: 402 of these showed a close match to at least one other subtype B sequence. Nine large clusters were identified on the basis of genetic distance; all were confirmed by Bayesian Monte Carlo Markov chain (MCMC) phylogenetic analysis. Overall, 25% of individuals with a close match with one sequence are linked to 10 or more others. Dated phylogenies of the clusters using a relaxed clock indicated that 65% of the transmissions within clusters took place between 1995 and 2000, and 25% occurred within 6 mo after infection. The likelihood that not all members of the clusters have been identified renders the latter observation conservative.
Conclusions
Reconstruction of the HIV transmission network using a dated phylogeny approach has revealed the HIV epidemic among MSM in London to have been episodic, with evidence of multiple clusters of transmissions dating to the late 1990s, a period when HIV prevalence is known to have doubled in this population. The quantitative description of the transmission dynamics among MSM will be important for parameterization of epidemiological models and in designing intervention strategies.
Using viral genotype data from HIV drug resistance testing at a London clinic, Andrew Leigh Brown and colleagues derive the structure of the transmission network through phylogenetic analysis.
Editors' Summary
Background.
Human immunodeficiency virus (HIV), the cause of acquired immunodeficiency syndrome (AIDS), is mainly spread through unprotected sex with an infected partner. Like other sexually transmitted diseases, HIV/AIDS spreads through networks of sexual contacts. The characteristics of these complex networks (which include people who have serial sexual relationships with single partners and people who have concurrent sexual relationships with several partners) affect how quickly diseases spread in the short term and how common the disease is in the long term. For many sexually transmitted diseases, sexual contact networks can be reconstructed from interview data. The information gained in this way can be used for partner notification so that transmitters of the disease and people who may have been unknowingly infected can be identified, treated, and advised about disease prevention. It can also be used to develop effective community-based prevention strategies.
Why Was This Study Done?
Although sexual contact networks have provided valuable information about the spread of many sexually transmitted diseases, they cannot easily be used to understand HIV transmission patterns. This is because the period of infectivity with HIV is long and the risk of infection from a single sexual contact with an infected person is low. Another way to understand the spread of HIV is through phylogenetics, which examines the genetic relatedness of viruses obtained from different individuals. Frequent small changes in the genetic blueprint of HIV allow the virus to avoid the human immune response and to become resistant to antiretroviral drugs. In this study, the researchers use recently developed analytical methods, viral sequences from a large proportion of a specific HIV-infected population, and information on when each sample was taken, to learn about transmission of HIV/AIDS in London among men who have sex with men (MSM; a term that encompasses gay, bisexual, and transgendered men and heterosexual men who sometimes have sex with men). This new approach, which combines information on viral genetic variation and viral population dynamics, is called “molecular phylodynamics.”
What Did the Researchers Do and Find?
The researchers compared the sequences of the genes encoding the HIV-1 protease and reverse transcriptase from more than 2,000 patients, mainly MSM, attending a large London HIV clinic between 1997 and 2003. 402 of these sequences closely matched at least one other subtype B sequence (the HIV/AIDS epidemic among MSM in the UK primarily involves HIV subtype B). Further analysis showed that the patients from whom this subset of sequences came formed six clusters of ten or more individuals, as well as many smaller clusters, based on the genetic relatedness of their HIV viruses. The researchers then used information on the date when each sample was collected and a “relaxed clock” approach (which accounts for the possibility that different sequences evolve at different rates) to determine dated phylogenies (patterns of genetic relatedness that indicate when gene sequences change) for the clusters. These phylogenies indicated that at least in one in four transmissions between the individuals in the large clusters occurred within 6 months of infection, and that most of the transmissions within each cluster occurred over periods of 3–4 years during the late 1990s.
What Do These Findings Mean?
This phylodynamic reconstruction of the HIV transmission network among MSM in a London clinic indicates that the HIV epidemic in this population has been episodic with multiple clusters of transmission occurring during the late 1990s, a time when the number of HIV infections in this population doubled. It also suggests that transmission of the virus during the early stages of HIV infection is likely to be an important driver of the epidemic. Whether these results apply more generally to the MSM population at risk for transmitting or acquiring HIV depends on whether the patients in this study are representative of that group. Additional studies are needed to determine this, but if the patterns revealed here are generalizable, then this quantitative description of HIV transmission dynamics should help in the design of strategies to strengthen HIV prevention among MSM.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050050.
Read a related PLoS Medicine Perspective article
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on all aspects of HIV/AIDS, including a list of organizations that provide information for gay men and MSM
The US Centers for Disease Control and Prevention provides information on HIV/AIDS and on HIV/AIDS among MSM (in English and Spanish)
Information is available from Avert, an international AIDS charity, on HIV, AIDS, and men who have sex with men
The Center for AIDS Prevention Studies (University of California, San Francisco) provides information on sexual networks and HIV prevention
The US National Center for Biotechnology Information provides a science primer on molecular phylogenetics
UK Collaborative Group on HIV Drug Resistance maintains a database of resistance tests
HIV i-Base offers HIV treatment information for health-care professionals and HIV-positive people
The NIH-funded HIV Sequence Database contains data on genetic sequences, resistance, immunology, and vaccine trials
doi:10.1371/journal.pmed.0050050
PMCID: PMC2267814  PMID: 18351795
7.  Mental Health and HIV Risk in Men Who Have Sex with Men 
Evidence-based HIV prevention interventions with men who have sex with men (MSM) in the United States have moderate effect sizes in reducing HIV sexual risk behavior. Mental health and psychosocial problems, which both disproportionately affect MSM populations and are implicated in HIV transmission risk behaviors, also likely interfere with the uptake of HIV behavioral interventions. Moreover, given that mental health and psychosocial problems such as depression, substance use, and violence frequently co-occur for many MSM (eg, as “syndemic conditions”), what is probably needed are combination prevention efforts, or prevention “cocktails,” similar to treatment “cocktails,” that address the psychological and behavioral mechanisms that interact to produce elevated risk for HIV. Such interventions should incorporate a holistic framework to address the sexual health and overall well-being of MSM. Addressing co-occurring psychosocial risk factors is apt to improve effect sizes of current HIV prevention interventions and allow for more effective uptake by MSM.
doi:10.1097/QAI.0b013e3181fbc939
PMCID: PMC3074520  PMID: 21406991
8.  Youth Living with HIV and Partner-specific Risk for the Secondary Transmission of HIV 
Sexually transmitted diseases  2009;36(7):439-444.
Summary
A comparison of risks for the secondary transmission of HIV between young HIV-infected women-who-have-sex-with-men (WSM) and men-who-have-sex-with-men (MSM) found that recent partner-specific sexual risk behaviors are high among both populations. However, differences in the specific behaviors between WSM and MSM support population-specific interventions to reduce the secondary transmission of HIV.
Background
Secondary transmission remains a significant concern among HIV-infected youth. Little is known, however, about how partner-specific sexual risk behaviors for the secondary transmission of HIV may differ between the two largest subgroups of HIV positive youth, women-who-have-sex-with-men (WSM) and men-who-have-sex-with-men (MSM),
Methods
During 2003-2004, a convenience sample of HIV-infected youth, 13-24 years of age, were recruited from 15 Adolescent Medicine Trials Network clinical sites. Approximately 10-15 youth were recruited at each site. Participants completed an ACASI survey including questions about sex partners in the past year. Cross-sectional data analyses, including bivariate and multivariable regressions using generalized estimating equations, were conducted during 2008 to compare recent partner-specific sexual risk behaviors between WSM and MSM.
Results
Of 409 participants, 91% (371) were included in this analysis, including 176 WSM and 195 MSM. Ninety-two percent (163 WSM, 177 MSM) provided information on characteristics of their sexual partners. There were significant differences between the two groups in recent partner-specific sexual risk behaviors including: lower rates of condom use at last sex among WSM (61% WSM vs. 78% MSM; p=0.0011); a larger proportion of the sex partners of MSM reported as concurrent (56% MSM vs. 36% WSM; p=0.0001); and greater use of hard drugs at last sex by MSM and/or their partner (18% MSM vs. 4% WSM; p=0.0008). When measuring risk as a composite measure of sexual risk behaviors known to be associated with HIV transmission, both groups had high rates of risky behaviors, 74.7% among young MSM compared to 68.1% of WSM.
Conclusions
These data suggest that recent partner-specific sexual risk behaviors for HIV transmission are high among young infected MSM and WSM. These findings suggest the need to offer interventions to reduce the secondary transmission of HIV to all HIV-positive youth in care. However, differences in risk behaviors between young MSM and WSM supports population-specific interventions.
doi:10.1097/OLQ.0b013e3181ad516c
PMCID: PMC2725398  PMID: 19525889
9.  Prevalence of Consensual Male–Male Sex and Sexual Violence, and Associations with HIV in South Africa: A Population-Based Cross-Sectional Study 
PLoS Medicine  2013;10(6):e1001472.
Using a method that offered complete privacy to participants, Rachel Jewkes and colleagues conducted a survey among South African men about their lifetime same-sex experiences.
Please see later in the article for the Editors' Summary
Background
In sub-Saharan Africa the population prevalence of men who have sex with men (MSM) is unknown, as is the population prevalence of male-on-male sexual violence, and whether male-on-male sexual violence may relate to HIV risk. This paper describes lifetime prevalence of consensual male–male sexual behavior and male-on-male sexual violence (victimization and perpetration) in two South African provinces, socio-demographic factors associated with these experiences, and associations with HIV serostatus.
Methods and Findings
In a cross-sectional study conducted in 2008, men aged 18–49 y from randomly selected households in the Eastern Cape and KwaZulu-Natal provinces provided anonymous survey data and dried blood spots for HIV serostatus assessment. Interviews were completed in 1,737 of 2,298 (75.6%) of enumerated and eligible households. From these households, 1,705 men (97.1%) provided data on lifetime history of same-sex experiences, and 1,220 (70.2%) also provided dried blood spots for HIV testing. 5.4% (n = 92) of participants reported a lifetime history of any consensual sexual activity with another man; 9.6% (n = 164) reported any sexual victimization by a man, and 3.0% (n = 51) reported perpetrating sexual violence against another man. 85.0% (n = 79) of men with a history of consensual sex with men reported having a current female partner, and 27.7% (n = 26) reported having a current male partner. Of the latter, 80.6% (n = 21/26) also reported having a female partner. Men reporting a history of consensual male–male sexual behavior are more likely to have been a victim of male-on-male sexual violence (adjusted odds ratio [aOR] = 7.24; 95% CI 4.26–12.3), and to have perpetrated sexual violence against another man (aOR = 3.10; 95% CI 1.22–7.90). Men reporting consensual oral/anal sex with a man were more likely to be HIV+ than men with no such history (aOR = 3.11; 95% CI 1.24–7.80). Men who had raped a man were more likely to be HIV+ than non-perpetrators (aOR = 3.58; 95% CI 1.17–10.9).
Conclusions
In this sample, one in 20 men (5.4%) reported lifetime consensual sexual contact with a man, while about one in ten (9.6%) reported experience of male-on-male sexual violence victimization. Men who reported having had sex with men were more likely to be HIV+, as were men who reported perpetrating sexual violence towards other men. Whilst there was no direct measure of male–female concurrency (having overlapping sexual relationships with men and women), the data suggest that this may have been common. These findings suggest that HIV prevention messages regarding male–male sex in South Africa should be mainstreamed with prevention messages for the general population, and sexual health interventions and HIV prevention interventions for South African men should explicitly address male-on-male sexual violence.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
AIDS first emerged in the early 1980s among gay men living in the US, but it soon became clear that AIDS also infects heterosexual men and women. Now, three decades on, globally, 34 million people (two-thirds of whom live in sub-Saharan Africa and half of whom are women) are infected with HIV, the virus that causes AIDS, and 2.5 million people become infected every year. HIV is most often spread by having unprotected sex with an infected partner, and most sexual transmission of HIV now occurs during heterosexual sex. However, 5%–10% of all new HIV infections still occur in men who have sex with men (MSM; homosexual, bisexual, and transgender men, and heterosexual men who sometimes have consensual sex with men). Moreover, in the concentrated HIV epidemics of high-income countries (epidemics in which the prevalence of HIV infection is more than 5% in at-risk populations such as sex workers but less than 1% in the general population), male-to-male sexual contact remains the most important transmission route, and MSM often have a higher prevalence of HIV infection than heterosexual men.
Why Was This Study Done?
By contrast to high-income countries, HIV epidemics in sub-Saharan Africa are generalized—the prevalence of HIV infection is 1% or more in the general population. Because male-to-male sexual behavior is criminalized in many African countries and because homosexuality is widely stigmatized, little is known about the prevalence of consensual male–male sexual behavior in sub-Saharan Africa. This information and a better understanding of male–female sexual concurrency (having overlapping sexual relationships with men and women) and of how male-to-male transmission contributes to generalized HIV epidemics is needed to inform the design of HIV prevention strategies for use in sub-Saharan Africa. In addition, very little is known about male-on-male sexual violence. Such violence is potentially important to study because we know that male-on-female violence is associated with increased HIV risk for both victims and perpetrators. In this cross-sectional study (an investigation that measures population characteristics at a single time point), the researchers use data from a population-based household survey to investigate the lifetime prevalence of consensual male–male sexual behavior and male-on-male sexual violence (victimization and perpetration) among men in South Africa and the association of these experiences with HIV infection.
What Did the Researchers Do and Find?
About 1,700 adult men from randomly selected households in the Eastern Cape and KwaZulu-Natal provinces of South Africa self-completed a survey that included questions about their lifetime history of same-sex experiences using audio-enhanced personal digital assistants, a data collection method that provided a totally private and anonymous environment for the disclosure of illegal and stigmatized behavior; 1,220 of them also provided dried blood spots for HIV testing. Ninety-two men (5.4% of the participants) reported consensual sexual activity (for example, anal or oral sex) with another man at some time during their life; 9.6% of the men reported that they had been forced to have sex with another man (sexual victimization), and 3% reported that they had perpetrated sexual violence against another man. Most of the men who reported consensual sex with men, including those with current male partners, reported that they had a current female partner. Men with a history of consensual male–male sexual behavior were more likely to have been a victim or perpetrator of male-on-male sexual violence than men without a history of such experiences. Finally, men who reported consensual oral or anal sex with a man were more likely to be HIV+ than men without such a history, and perpetrators of male-on-male sexual violence were more likely to be HIV+ than non-perpetrators.
What Do These Findings Mean?
These findings provide new information about male–male sexual behaviors, male-on-male sexual violence, male–female concurrency, and HIV prevalence among men in two South African provinces. The precision of these findings is likely to be affected by the small numbers of men reporting a history of consensual male–male sexual behavior and of male-on-male sexual violence. Importantly, because the study was cross-sectional, these findings cannot indicate whether the association between consensual male–male sexual behaviors and increased risk of male-on-male sexual violence is causal. Moreover, these findings may not be generalizable to other regions of South Africa or to other African countries. Nevertheless, these findings suggest that information about the risks of male–male sexual behaviors should be included in HIV prevention strategies targeted at the general population in South Africa and that HIV prevention interventions for South African men should explicitly address male-on-male sexual violence. Similar HIV prevention strategies may also be suitable for other African countries, but are likely to succeed only in countries that have, like South Africa, decriminalized consensual homosexual behavior.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001472.
This study is further discussed in a PLOS Medicine Perspective by Jerome Singh
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, including summaries of recent research findings on HIV care and treatment
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on HIV and men who have sex with men, on HIV prevention, and on AIDS in Africa (in English and Spanish)
The US Centers for Disease Control and Prevention also has information about HIV/AIDS among men who have sex with men (in English and Spanish)
Patient stories about living with HIV/AIDS are available through Avert; the charity website Healthtalkonline also provides personal stories about living with HIV
doi:10.1371/journal.pmed.1001472
PMCID: PMC3708702  PMID: 23853554
10.  The Potential Impact of Pre-Exposure Prophylaxis for HIV Prevention among Men Who Have Sex with Men and Transwomen in Lima, Peru: A Mathematical Modelling Study 
PLoS Medicine  2012;9(10):e1001323.
Gabriela Gomez and colleagues developed a mathematical model of the HIV epidemic among men who have sex with men and transwomen in Lima, Peru to explore whether HIV pre-exposure prophylaxis could be a cost-effective addition to existing HIV prevention strategies.
Background
HIV pre-exposure prophylaxis (PrEP), the use of antiretroviral drugs by uninfected individuals to prevent HIV infection, has demonstrated effectiveness in preventing acquisition in a high-risk population of men who have sex with men (MSM). Consequently, there is a need to understand if and how PrEP can be used cost-effectively to prevent HIV infection in such populations.
Methods and Findings
We developed a mathematical model representing the HIV epidemic among MSM and transwomen (male-to-female transgender individuals) in Lima, Peru, as a test case. PrEP effectiveness in the model is assumed to result from the combination of a “conditional efficacy” parameter and an adherence parameter. Annual operating costs from a health provider perspective were based on the US Centers for Disease Control and Prevention interim guidelines for PrEP use. The model was used to investigate the population-level impact, cost, and cost-effectiveness of PrEP under a range of implementation scenarios. The epidemiological impact of PrEP is largely driven by programme characteristics. For a modest PrEP coverage of 5%, over 8% of infections could be averted in a programme prioritising those at higher risk and attaining the adherence levels of the Pre-Exposure Prophylaxis Initiative study. Across all scenarios, the highest estimated cost per disability-adjusted life year averted (uniform strategy for a coverage level of 20%, US$1,036–US$4,254) is below the World Health Organization recommended threshold for cost-effective interventions, while only certain optimistic scenarios (low coverage of 5% and some or high prioritisation) are likely to be cost-effective using the World Bank threshold. The impact of PrEP is reduced if those on PrEP decrease condom use, but only extreme behaviour changes among non-adherers (over 80% reduction in condom use) and a low PrEP conditional efficacy (40%) would adversely impact the epidemic. However, PrEP will not arrest HIV transmission in isolation because of its incomplete effectiveness and dependence on adherence, and because the high cost of programmes limits the coverage levels that could potentially be attained.
Conclusions
A strategic PrEP intervention could be a cost-effective addition to existing HIV prevention strategies for MSM populations. However, despite being cost-effective, a substantial expenditure would be required to generate significant reductions in incidence.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Without a vaccine, the only ways to halt the global HIV epidemic are prevention strategies that reduce transmission of the HIV virus. Up until recently, behavioral strategies such as condom use and reduction of sexual partners have been at the center of HIV prevention. In the past few years, several biological prevention measures have also been shown to be effective in reducing (though not completely preventing) HIV transmission. These include male circumcision, treatment for prevention (giving antiretroviral drugs to HIV-infected people, before they need it for their own health, to reduce their infectiousness) and pre-exposure prophylaxis (or PrEP), in which HIV-negative people use antiretroviral drugs to protect themselves from infection. One PrEP regimen (a daily pill containing two different antiretrovirals) has been shown in a clinical trial to reduce new infections by 44% in of men who have sex with men (MSM). In July 2012, the US Food and Drug Administration approved this PrEP regimen to reduce the risk of HIV infection in uninfected men and women who are at high risk of HIV infection and who may engage in sexual activity with HIV-infected partners. The approval makes it clear that PrEP needs to be used in combination with safe sex practices.
Why Was This Study Done?
Clinical trials have shown that PrEP can reduce HIV infections among participants, but they have not examined the consequences PrEP could have at the population level. Before decision-makers can decide whether to invest in PrEP programs, they need to know about the costs and benefits at the population level. Besides the price of the drug itself, the costs include HIV testing before starting PrEP, as well as regular tests thereafter. The health benefits of reducing new HIV infections are calculated in “disability-adjusted life years” (or DALYs) averted. One DALY is equal to one year of healthy life lost. Other benefits include future savings in lifelong HIV/AIDS treatment for every person whose infection is prevented by PrEP.
This study estimates the potential costs and health benefits of several hypothetical PrEP roll-out scenarios among the community of MSM in Lima, Peru. The scientists chose this community because many of the participants in the clinical trial that showed that PrEP can reduce infections came from this community, and they therefore have some knowledge on how PrEP affects HIV infection rates and behavior in this population. Because the HIV epidemic in Lima is concentrated among MSM, similar to most of Latin America and several other developed countries, the results might also be relevant for the evaluation of PrEP in other places.
What Did the Researchers Do and Find?
For their scenarios, the researchers looked at “high coverage” and “low coverage” scenarios, in which 20% and 5% of uninfected individuals use PrEP, respectively. They also divided the MSM community into those at lower risk of becoming infected and those at higher risk. The latter group consisted of transwomen at higher risk (transsexuals and transvestites with many sexual partners) and male sex workers. In a “uniform coverage” scenario, PrEP is equally distributed among all MSM. “Prioritized scenarios” cover transwomen at higher risk and sex workers preferentially. Two additional important factors for the estimated benefits are treatment adherence (i.e., whether people take the pills they have been prescribed faithfully over long periods of time even though they are not sick) and changes in risk behavior (i.e., whether the perceived protection provided by PrEP leads to more unprotected sex).
The cost estimates for PrEP included the costs of the drug itself and HIV tests prior to PrEP prescription and at three-month intervals thereafter, as well as outreach and counseling services and condom and lubricant promotion and provision.
To judge whether under the various scenarios PrEP is cost-effective, the researchers applied two commonly used but different cost-effectiveness thresholds. The World Health Organization's WHO-CHOICE initiative considers an intervention cost-effective if its cost is less than three times the gross domestic product (GDP) per capita per DALY averted. For Peru, this means an intervention should cost less than US$16,302 per DALY. The World Bank has more stringent criteria: it considers an intervention cost-effective for a middle-income country like Peru if it costs less than US$500 per DALY averted.
The researchers estimate that PrEP is cost-effective in Lima's MSM population for most scenarios by WHO-CHOICE guidelines. Only scenarios that prioritize PrEP to those most likely to become infected (i.e., transwomen at higher risk and sex workers) are cost-effective (and only barely) by the more stringent World Bank criteria. If the savings on antiretroviral drugs to treat people with HIV (those who would have become infected without PrEP) are included in the calculation, most scenarios become cost-effective, even under World Bank criteria.
The most cost-effective scenario, namely, having a modest coverage of 5%, prioritizing PrEP to transwomen at higher risk and sex workers, and assuming fairly high adherence levels among PrEP recipients, is estimated to avert about 8% of new infections among this community over ten years.
What Do these Findings Mean?
These findings suggest that under some circumstances, PrEP could be a cost-effective tool to reduce new HIV infections. However, as the researchers discuss, PrEP is expensive and only partly effective. Moreover, its effectiveness depends on two behavioral factors—adherence to a strict drug regimen and continued practicing of safe sex—both of which remain hard to predict. As a consequence, PrEP alone is not a valid strategy to prevent new HIV infections. It needs instead to be considered as one of several available tools. If and when PrEP is chosen as part of an integrated prevention strategy will depend on the specific target population, the overall funds available, and how well its cost-effectiveness compares with other prevention measures.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001323.
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and a section on PrEP
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including HIV prevention
AVAC Global Advocacy for HIV Prevention provides up-to-date information on HIV prevention, including PrEP
The US Centers for Disease Control and Prevention also has information on PrEP
The World Health Organization has a page on its WHO-CHOICE criteria for cost-effectiveness
doi:10.1371/journal.pmed.1001323
PMCID: PMC3467261  PMID: 23055836
11.  Application of Syndemic Theory to Black Men Who Have Sex with Men in the Multicenter AIDS Cohort Study 
This study analyzed data from a large prospective epidemiologic cohort study among men who have sex with men (MSM), the Multicenter AIDS Cohort Study, to assess syndemic relationships among Black MSM in the cohort (N = 301). We hypothesized that multiple interconnections among psychosocial health conditions would be found among these men, defining syndemic conditions. Constituents of syndemic conditions measured included reported depression symptoms, sexual compulsiveness, substance use, intimate partner violence (IPV), and stress. We found significant evidence of syndemics among these Black men: depression symptoms were independently associated with sexual compulsiveness (odds ratios [OR]: 1.88, 95% CI = 1.1, 3.3) and stress (OR: 2.67, 95% CI = 1.5, 4.7); sexual compulsiveness was independently associated with stress (OR: 2.04, 95% CI = 1.2, 3.5); substance misuse was independently associated with IPV (OR: 2.57, 95% CI = 1.4, 4.8); stress independently was associated with depression symptoms (OR: 2.67, 95% CI = 1.5, 4.7), sexual compulsiveness (OR: 2.04, 95% CI = 1.2, 3.5) and IPV (OR: 2.84, 95% CI = 1.6, 4.9). Moreover, men who reported higher numbers of syndemic constituents (three or more conditions) reportedly engaged in more unprotected anal intercourse compared to men who had two or fewer health conditions (OR: 3.46, 95% CI = 1.4–8.3). Findings support the concept of syndemics in Black MSM and suggest that syndemic theory may help explain complexities that sustain HIV-related sexual transmission behaviors in this group.
doi:10.1007/s11524-012-9674-x
PMCID: PMC3535137  PMID: 22383094
HIV; Syndemics; Black men; Sexual risk; Epidemiology
12.  Assessing motivations to engage in intentional condomless anal intercourse in HIV-risk contexts (“bareback sex”) among men who have sex with men 
Background
While condom use is an effective barrier against HIV transmission, some men who have sex with men (MSM) engage in bareback sex (unprotected anal sex in risky contexts) and increase their risk for HIV (re)infection. Understanding MSM's decision to bareback (vis-à-vis condom use) is essential to develop effective HIV/AIDS prevention programs for this population.
Method
An ethnically diverse sample of men who bareback (n=120) was recruited exclusively on the Internet and stratified to include two-thirds who reported both URAI and being HIV-uninfected. We use exploratory factor analysis to explore the domains within the DBB scale, and test the association between DBB and risky sexual behaviors.
Results
HIV-positive MSM (n=31) reported higher costs/losses associated with condom use than HIV-negative men (n=89). We found two underlying factors in the DBB scale: a Coping with Social Vulnerabilities subscale (8 items; α = .89) and a Pleasure & Emotional Connection subscale (5 items; α = .92). We found a positive association between DBB (i.e. greater gains associated with bareback sex) and URAI occasions, number of partners, and having one or more serodiscordant partners in the past 3 months.
Conclusions
MSM may avoid using condoms in order to cope with psychosocial vulnerabilities and create intimacy with other MSM. This population could benefit from alternatives to condoms such as pre/post exposure prophylaxis and rectal microbicides.
doi:10.1521/aeap.2009.21.2.156
PMCID: PMC2699594  PMID: 19397437
Condom use; Bareback; MSM; decision-making; scale development
13.  ANRS–COM'TEST: description of a community-based HIV testing intervention in non-medical settings for men who have sex with men 
BMJ Open  2012;2(2):e000693.
Objective
To describe a community-based HIV testing programme.
Design and setting
An intervention of HIV voluntary testing conducted in non-medical settings in four French cities.
Participants
Men who have sex with men (MSM).
Intervention
Counselling and rapid HIV testing staffed by trained personnel from an HIV/AIDS community-based organisation.
Primary and secondary outcome measures
The population that has taken hold of the intervention and the satisfaction of participants. Data were collected on demographics, HIV testing history, sexual practices and satisfaction with the testing programme.
Results
532 MSM were tested between February 2009 and June 2010, of whom 49 (9%) were tested two or more times. 468 MSM (88%) had casual male partners in the previous 6 months, and 152 (35%) reported having unprotected anal intercourse with risky casual partners (HIV infected or HIV serostatus unknown). 159 men (30%) had not been tested in the previous 2 years, and 50 (31%) of whom had unprotected anal intercourse with risky casual partners. Among the 15 patients who tested positive (2.8%), 12 (80%) received confirmation and were linked to care (median CD4 cell count =550/mm3). Satisfaction was high: 92% reported being ‘very satisfied’ with their experience. Steps of counselling and testing procedure were respected by testers and difficulties in handling tests were rare.
Conclusions
This community-based HIV testing programme reached high-risk MSM, of whom a substantial proportion had not been tested lately. This novel service supplements pre-existing HIV testing services and increases access to HIV testing in high-risk groups.
Article summary
Article focus
How extend testing facilities to reach and test for HIV more MSM and diagnose HIV-infected MSM earlier?
The presence of peers and non-clinical staff members who address sexuality more openly and avoid medical jargon during counselling sessions could offset cultural barriers and reduce fears of HIV and associated stigma.
The article describes an experimental programme of community-based HIV testing: the population reached, the quality of the programme and the satisfaction of participants.
Key messages
This community-based HIV testing and counselling programme reaches MSM with high-risk sexual behaviour, a substantial proportion of whom has not tested for HIV recently.
Community testers are able to perform rapid HIV test into a comprehensive prevention approach in line with participant's life.
2.8% of participants tested positive. Infection was confirmed in all cases, 80% were linked to care. Cases were diagnosed at early stages of disease.
Strengths and limitations of this study
This HIV testing and counselling programme is exclusively based on MSM community, and continuing the prevention counselling with the awareness of the HIV serostatus includes testing into a comprehensive prevention approach.
Community-based HIV testing programmes may be attractive and efficient in large urban areas (like Paris), but perhaps less so in smaller cities, where an outreach approach may work better.
The number of HIV diagnoses was small; the prevalence and median CD4 count among the few HIV-infected participants should therefore be interpreted with caution.
doi:10.1136/bmjopen-2011-000693
PMCID: PMC3323802  PMID: 22466158
14.  Evidence for a Syndemic in Aging HIV-positive Gay, Bisexual, and Other MSM: Implications for a Holistic Approach to Prevention and Healthcare 
Natural resource modeling  2013;36(2):10.1111/napa.12009.
The theory of syndemics has been widely applied in HIV prevention studies of gay, bisexual, and other MSM over the last decade. Our investigation is the first to consider the applicability of the theory in a sample of aging (ages 50 and over) HIV-positive MSM, which is a growing population in the United States. A sample of 199 men were actively recruited and assessed in terms of mental health and drug use burden, as well as sexual risk behaviors. Bivariate and multivariable analyses indicate a high level of association between psychosocial burdens (i.e., drug use and mental health) and same-sex unprotected sexual behaviors, providing initial support for the applicability of the theory of syndemics to this population. Further support can be seen in participants’ narratives. Findings suggest the mutually reinforcing nature of drug use, psychiatric disorders, and unprotected sexual behavior in older, HIV-positive, gay, bisexual, and other MSM, highlighting the need for holistic strategies to prevention and care among this population of older and sexually active individuals. In short, the generation of gay men who came of age in the late 1970s and 1980s, “the AIDS Generation,” are continuing to mature such that further efforts must be enacted to meet the multidimensional nature of these men’s physical, mental, and sexual health needs.
doi:10.1111/napa.12009
PMCID: PMC3859453  PMID: 24347817
HIV-positive men; gay, bisexual and MSM; aging; syndemic; sexual risk-taking; drug use; mental health
15.  Psychosocial Health Problems Associated with Increased HIV Risk Behavior among Men Who Have Sex with Men in Nepal: A Cross-Sectional Survey 
PLoS ONE  2013;8(3):e58099.
Background
Men who have sex with men (MSM) are marginalized, hidden, underserved and at high risk for HIV in Nepal. We examined the association between MSM sub-populations, psychosocial health problems and support, access to prevention and non-use of condoms.
Methods
Between September-November of 2010, a cross-sectional survey on HIV-related risk behavior was performed across Nepal through snowball sampling facilitated by non-governmental organizations, recruiting 339 MSM, age 15 or older. The primary outcomes were: (a) non-use of condoms at least once in last three anal sex encounters with men and (b) non-use of condoms with women in the last encounter. The secondary outcome was participation in HIV prevention interventions in the past year.
Results
Among the 339 MSM interviewed, 78% did not use condoms at their last anal sex with another man, 35% did not use condoms in their last sex with a woman, 70% had experienced violence in the last 12 months, 61% were experiencing depression and 47% had thought of committing suicide. After adjustment for age, religion, marital status, and MSM subpopulations (bisexual, ta, meti, gay), non-use of condoms at last anal sex with a man was significantly associated with non-participation in HIV interventions, experience of physical and sexual violence, depression, repeated suicidal thoughts, small social support network and being dissatisfied with social support. Depression was marginally associated with non-use of condoms with women. The findings suggest that among MSM who reported non-use of condoms at last anal sex, the ta subgroup and those lacking family acceptance were the least likely to have participated in any preventive interventions.
Conclusions
MSM in Nepal have a prevalence of psychosocial health problems in turn associated with high risk behavior for HIV. Future HIV prevention efforts targeting MSM in Nepal should cover all MSM subpopulations and prioritize psychosocial health interventions.
doi:10.1371/journal.pone.0058099
PMCID: PMC3596342  PMID: 23516434
16.  The characterisation of sexual behaviour in Chinese male university students who have sex with other men: A cross-sectional study 
BMC Public Health  2008;8:250.
Background
The risks for Chinese male university students who have sex with other men (MSM) have not been compared with those for non-MSM students. This information is important for the development of targeted HIV prevention programmes for this population.
Methods
Sexually active MSM and non-MSM students were compared for demographic characteristics, sexual behaviour, and related psychosocial variables using bivariate analyses. The data were a subset drawn from a large-scale cross-sectional questionnaire survey of sexually active male students conducted at two universities in a large city in Zhejiang Province, China, in 2003.
Results
Of 1824 sexually active male students, 68 (3.7%) reported having had sex with a man at least once; 33.8% of these 68 men had also had female partners. Compared with non-MSM students, MSM students were 3–6.5 times more likely to have had sexual encounters with casual or commercial sex partners and were three times less likely to have protected sex in the past year or during their lifetime. They were three to five times more likely to have had multiple partners and 15 times more likely to have had a sexually transmitted disease (STD). In addition, the MSM students knew half as much about HIV and had less condom-decision than did non-MSM students and were two times more accepting of commercial sex. However, the MSM students were twice as aware of the risks for HIV infection.
Conclusion
MSM composed 3–4% of the male sexually active university student population studied and was found to be at greater risk than non-MSM students for STD/HIV infection. There is an urgent need for STD/HIV programmes in university health services that take into consideration the sexuality and psychosocial issues of MSM students.
doi:10.1186/1471-2458-8-250
PMCID: PMC2503976  PMID: 18647381
17.  A qualitative assessment of health seeking practices among and provision practices for men who have sex with men in Malawi 
Background
In the context of a generalized epidemic and criminalization of homosexuality, men who have sex with men (MSM) in Malawi have a disproportionate burden of HIV compared to other adults. Past research has documented low uptake of HIV prevention and health services among MSM, self-reported fear of seeking health services, and concerns of disclosure of sexual orientation and discrimination in health settings. Qualitative research was conducted among MSM and health service providers in Blantyre, Malawi to understand underlying factors related to disclosure and health seeking behaviors and inform the development of a community-based comprehensive HIV prevention intervention.
Methods
Using peer recruitment, eight MSM participants representing a range of ages, orientations, and social and behavioral characteristics were enrolled for in-depth interviews. Five service providers were recruited from the district hospital, local health and STI clinics, and a HIV prevention service organization. We use the Health Belief Model as a framework to interpret the influential factors on 1) health seeking and uptake among MSM, and 2) influences on provision of services by healthcare providers for MSM.
Results
Results highlight disclosure fears among MSM and, among providers, a lack of awareness and self-efficacy to provide care in the face of limited information and political support. Service providers reported concerns of adverse repercussions related to the provision of services to men in same sex sexual relationships. Some MSM demonstrated awareness of HIV risk but believed that within the wider MSM community, there was a general lack of HIV information for MSM, low awareness of appropriate prevention, and low perception of risks related to HIV infection.
Conclusions
Qualitative research highlights the need for appropriate information on both HIV risks and acceptable, effective HIV prevention options for MSM. Information and educational opportunities should be available to the wider MSM community and the health sector. Health sector interventions may serve to increase cultural and clinical competency to address health problems experienced by MSM. To ensure availability and use of services in light of the criminalization and stigmatization of same sex practices, there is need to increase the safety of uptake and provision of these services for MSM.
doi:10.1186/1472-698X-14-20
PMCID: PMC4049421  PMID: 24893654
Health knowledge; Attitudes; Practice; HIV/AIDS; Men who have sex with men (MSM); Stigma; Malawi
18.  Men Who Have Sex with Men and Human Immunodeficiency Virus/Sexually Transmitted Disease Control in China 
Cell research  2005;15(11-12):858-864.
Objectives:
To address the role of men who have sex with men (MSM) in the human immunodeficiency virus (HIV)/sexually transmitted disease (STD) epidemic in China.
Goal:
To explore the prevalence of risky sexual behaviors and the existing prevention efforts among men who have sex with men (MSM) in China.
Study Design:
Review of behavioral and STD/HIV prevention studies addressing MSM in China.
Results:
Sexual risk behaviors including unprotected group sex, anal sex, casual sex, and commercial sex were prevalent among Chinese MSM. Many Chinese MSM also engaged in unprotected sex with both men and women. Most MSM either did not perceive that they were at risk of HIV/AIDS or underestimated their risk of infection. Surveillance and intervention research among these men are still in the preliminary stages.
Conclusions:
Chinese MSM are at risk for HIV/STD infection and potential transmission of HIV to the general population. In addition to sexual risk reduction among MSM, reduction of homosexualityrelated stigma should be part of effective intervention efforts. Volunteers from the MSM community and health care workers in primary health care system may serve as valuable resources for HIV/STD prevention and control among MSM.
doi:10.1038/sj.cr.7290359
PMCID: PMC1791010  PMID: 16354560
19.  Sexual Health and Men Who Have Sex with Men in Vietnam: An Integrated Approach to Preventive Health Care 
Background. While HIV infection among men who have sex with men (MSM) in Vietnam has received increasing attention, most studies focus on HIV knowledge and established risk factors such as injection drug use. This paper proposes to address HIV risk among MSM from an integrated approach to preventive care that takes into account syndemic conditions such as substance use, mental health, and stigma, the latter of which prevents MSM from accessing health services. Method. Current studies related to MSM in Vietnam from 2000 onwards, gathered from peer-reviewed as well as non-peer-reviewed sources, were examined. Results. HIV and STI prevalence among MSM varied significantly by location, and yet HIV prevalence has increased significantly over the past few years. Most studies have focused on sexual risk behaviors, paying little attention to the broad spectrum of sexual health, including noninjecting drug use, heavy alcohol consumption, high rates of mental health distress and anxiety, and stigma. Conclusion. Future research and interventions targeting MSM in Vietnam should address their vulnerability to HIV from an integrated approach that pays attention to both sexual health and syndemic conditions.
doi:10.1155/2012/796192
PMCID: PMC3479935  PMID: 23119171
20.  HIV-1 Transmission during Early Infection in Men Who Have Sex with Men: A Phylodynamic Analysis 
PLoS Medicine  2013;10(12):e1001568.
Erik Volz and colleagues use HIV genetic information from a cohort of men who have sex with men in Detroit, USA to dissect the timing of onward transmission during HIV infection.
Please see later in the article for the Editors' Summary
Background
Conventional epidemiological surveillance of infectious diseases is focused on characterization of incident infections and estimation of the number of prevalent infections. Advances in methods for the analysis of the population-level genetic variation of viruses can potentially provide information about donors, not just recipients, of infection. Genetic sequences from many viruses are increasingly abundant, especially HIV, which is routinely sequenced for surveillance of drug resistance mutations. We conducted a phylodynamic analysis of HIV genetic sequence data and surveillance data from a US population of men who have sex with men (MSM) and estimated incidence and transmission rates by stage of infection.
Methods and Findings
We analyzed 662 HIV-1 subtype B sequences collected between October 14, 2004, and February 24, 2012, from MSM in the Detroit metropolitan area, Michigan. These sequences were cross-referenced with a database of 30,200 patients diagnosed with HIV infection in the state of Michigan, which includes clinical information that is informative about the recency of infection at the time of diagnosis. These data were analyzed using recently developed population genetic methods that have enabled the estimation of transmission rates from the population-level genetic diversity of the virus. We found that genetic data are highly informative about HIV donors in ways that standard surveillance data are not. Genetic data are especially informative about the stage of infection of donors at the point of transmission. We estimate that 44.7% (95% CI, 42.2%–46.4%) of transmissions occur during the first year of infection.
Conclusions
In this study, almost half of transmissions occurred within the first year of HIV infection in MSM. Our conclusions may be sensitive to un-modeled intra-host evolutionary dynamics, un-modeled sexual risk behavior, and uncertainty in the stage of infected hosts at the time of sampling. The intensity of transmission during early infection may have significance for public health interventions based on early treatment of newly diagnosed individuals.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Since the first recorded case of AIDS in 1981, the number of people infected with HIV, the virus that causes AIDS, has risen steadily. About 34 million people are currently HIV-positive, and about 2.5 million people become newly infected with HIV every year. Because HIV is usually transmitted through unprotected sex with an infected partner, individuals can reduce their risk of infection by abstaining from sex, by having only one or a few partners, and by always using condoms. Most people do not become ill immediately after infection with HIV, although some develop a short flu-like illness. The next stage of HIV infection, which may last more than ten years, also has no major symptoms, but during this stage, HIV slowly destroys immune system cells. Eventually, the immune system can no longer fight off infections by other disease-causing organisms, and HIV-positive people then develop one or more life-threatening AIDS-defining conditions, including unusual infections and specific types of cancer. HIV infection can be controlled, but not cured, by taking a daily cocktail of antiretroviral drugs.
Why Was This Study Done?
The design of effective programs to prevent the spread of HIV/AIDS depends on knowing how HIV transmissibility varies over the course of HIV infection. Consider, for example, a prevention strategy that focuses on increasing treatment rates: antiretroviral drugs, in addition to reducing illness and death among HIV-positive people, reduce HIV transmission from HIV-positive individuals. “Treatment as prevention” can only block transmissions that occur after diagnosis and entry into care. However, the transmissibility of HIV per sexual contact depends on a person's viral load, which peaks during early HIV infection, when people are often unaware of their HIV status and may still be following the high-risk patterns of sexual behavior that caused their own infection. Epidemiological surveillance data (information on HIV infections within populations) can be used to estimate how many new HIV infections occur within a population annually (HIV incidence) and the proportion of the population that is HIV-positive (HIV prevalence), but cannot be used to estimate the timing of transmission events. In this study, the researchers use “phylodynamic analysis” to estimate HIV incidence and prevalence and the timing of HIV transmission during infection. HIV, like many other viruses, rapidly accumulates genetic changes. The timing of transmission influences the pattern of these changes. Viral phylodynamic analysis—the quantitative study of how epidemiological, immunological, and evolutionary processes shape viral phylogenies (evolutionary trees)—can therefore provide estimates of transmission dynamics.
What Did the Researchers Do and Find?
The researchers obtained HIV sequence data (collected for routine surveillance of antiretroviral resistance mutations) and epidemiological surveillance data (including information on the stage of infection at diagnosis) for 662 HIV-positive men who have sex with men living in the Detroit metropolitan area of Michigan. They constructed a phylogenetic tree from the sequences using a “relaxed clock” approach and then fitted an epidemiological model (a mathematical model that represents the progress of individual patients through various stages of HIV infection) to the sequence data. Their approach, which integrates surveillance data and genetic data, yielded estimates of HIV incidence and prevalence among the study population similar to those obtained from surveillance data alone. However, it also provided information about HIV transmission that could not be obtained from surveillance data alone. In particular, it allowed the researchers to estimate that, in the current HIV epidemic among men who have sex with men in Detroit, 44.7% of HIV transmissions occur during the first year of infection.
What Do These Findings Mean?
The robustness of these findings depends on the validity of the assumptions included in the researchers' population genetic model and on the accuracy of the data fed into the model, and may not be generalizable to other cities or to other risk groups. Nevertheless, the findings of this analysis, which can be repeated in any setting where HIV sequence data for individual patients can be linked to patient-specific clinical and behavioral information, have important implications for HIV control strategies based on the early treatment of newly diagnosed individuals. Because relatively few infected individuals are diagnosed during early HIV infection, when the HIV transmission rate is high, it is unlikely, suggest the researchers, that the “treatment as prevention” strategy will effectively control the spread of HIV unless there are very high rates of HIV testing and treatment.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001568.
This study is further discussed in a PLOS Medicine Perspective by Timothy Hallett
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS and summaries of recent research findings on HIV care and treatment
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on HIV treatment as prevention (in English and Spanish)
The PLOS Medicine Collection Investigating the Impact of Treatment on New HIV Infections provides more information about HIV treatment as prevention
A PLOS Computational Biology Topic Page (a review article that is a published copy of record of a dynamic version of the article as found in Wikipedia) about viral phylodynamics is available
The US National Institute of Health–funded HIV Sequence Database contains HIV sequences and tools to analyze these sequences
Patient stories about living with HIV/AIDS are available through Avert; the charity website Healthtalkonline also provides personal stories about living with HIV
doi:10.1371/journal.pmed.1001568
PMCID: PMC3858227  PMID: 24339751
21.  Sexual Mixing Patterns and Partner Characteristics of Black MSM in Massachusetts at Increased Risk for HIV Infection and Transmission 
Black men who have sex with men (MSM) are at increased risk for HIV infection in the United States compared to other MSM. The aim of this study was to investigate Black MSM’s sexual mixing patterns and partner characteristics in relation to sexual risk taking, as a possible explanation for this observed increase in HIV incidence. Between January and July 2008, 197 Black MSM were recruited via modified respondent-driven sampling and completed optional pretest and post-test HIV serological testing, counseling, and a demographic, behavioral, and psychosocial assessment battery. Bivariate and multivariable logistic regression procedures were used to examine predictors of risky sex across partner types. Overall, 18% of the sample was HIV-infected; 50% reported unprotected intercourse with men, 30% with women, and 5% with transgender partners. Fifty-three percent identified as bisexual or straight, although all reported oral or anal sex with another man in the prior 12 months. Significant predictors of engaging in at least one episode of: (1) serodiscordant unprotected anal sex (UAS) with a male partner in the past 12 months: individuals at risk for social isolation (AOR = 4.23; p = 0.03), those with unstable housing (AOR = 4.19; p = 0.03), and those who used poppers at least weekly during sex (AOR = 5.90; p = 0.05); (2) UAS and/or unprotected vaginal intercourse with a female partner in the past 12 months: those with unstable housing (AOR = 4.85; p = 0.04), those who used cocaine at least weekly during sex (AOR = 16.78; p = 0.006), being HIV-infected (AOR = 0.07; p = 0.02), and feeling social norms favor condom use (AOR = 0.60; p = 0.05); (3) UAS with the participants’ most recent nonmain male sex partner: use of alcohol and drugs during last sex by participant (AOR = 4.04; p = 0.01), having sex with a Hispanic/Latino male (AOR = 2.71; p = 0.04) or a Black male (AOR = 0.50; p = 0.05) compared to a White male, and lower education (AOR = 1.31; p = 0.02). Findings suggest that sexual risk behaviors of Black MSM differ across partner type and by the characteristics of their sexual networks and that this subpopulation of MSM are at high risk for HIV acquisition and transmission. Effective prevention strategies need to address the distinct sexual and behavioral risk patterns presented by different sexual partnerships reported by Black MSM.
doi:10.1007/s11524-009-9363-6
PMCID: PMC2704278  PMID: 19466554
HIV/AIDS; STD; African American/Black; MSM; Prevention
22.  A Syndemic including Cigarette Smoking and Sexual Risk Behaviors among a Sample of MSM in Shanghai, China 
Drug and alcohol dependence  2013;132(0):265-270.
Objectives
We explored possible correlates of cigarette smoking and their associations with levels of smoking among a sample of Chinese men who have sex with men (MSM). We also explored the syndemic associations of substance use and psychosocial problems on sexual risk behaviors.
Methods
Cross-sectional data collection from 404 MSM in Shanghai, China.
Results
MSM exhibit a high prevalence of smoking (66.3%). Both light and heavy smoking were associated with alcohol and drug use, depression, intimate partner violence, sexual attitudes, and gay identity (though the associations for light smokers were moderate compared to those for heavy smokers).
Conclusions
Our findings indicate the presence of a health syndemic among MSM, and suggest that smoking prevention and cessation and other substance abuse interventions should be integrated into efforts preventing sexual risk behaviors among MSM.
doi:10.1016/j.drugalcdep.2013.02.016
PMCID: PMC3726538  PMID: 23517682
Chinese MSM; Smoking; Health Syndemics; prevention; cessation
23.  Measuring Population Transmission Risk for HIV: An Alternative Metric of Exposure Risk in Men Who Have Sex with Men (MSM) in the US 
PLoS ONE  2012;7(12):e53284.
Background
Various metrics for HIV burden and treatment success [e.g. HIV prevalence, community viral load (CVL), population viral load (PVL), percent of HIV-positive persons with undetectable viral load] have important public health limitations for understanding disparities.
Methods and Findings
Using data from an ongoing HIV incidence cohort of black and white men who have sex with men (MSM), we propose a new metric to measure the prevalence of those at risk of transmitting HIV and illustrate its value. MSM with plasma VL>400 copies/mL were defined as having ‘transmission risk’. We calculated HIV prevalence, CVL, PVL, percent of HIV-positive with undetectable viral loads, and prevalence of plasma VL>400 copies/ml (%VL400) for black and white MSM. We used Monte Carlo simulation incorporating data on sexual mixing by race to estimate exposure of black and white HIV-negative MSM to a partner with transmission risk via unprotected anal intercourse (UAI). Of 709 MSM recruited, 42% (168/399) black and 14% (44/310) white MSM tested HIV-positive (p<.0001). No significant differences were seen in CVL, PVL, or percent of HIV positive with undetectable viral loads. The %VL400 was 25% (98/393) for black vs. 8% (25/310) for white MSM (p<.0001). Black MSM with 2 UAI partners were estimated to have 40% probability (95% CI: 35%, 45%) of having ≥1 UAI partner with transmission risk vs. 20% for white MSM (CI: 15%, 24%).
Discussion
Despite similarities in other metrics, black MSM in our cohort are three times as likely as white MSM to have HIV transmission risk. With comparable risk behaviors, HIV-negative black MSM have a substantially higher likelihood of encountering a UAI partner at risk of transmitting HIV. Our results support increasing HIV testing, linkage to care, and antiretroviral treatment of HIV-positive MSM to reduce prevalence of those with transmission risk, particularly for black MSM.
doi:10.1371/journal.pone.0053284
PMCID: PMC3532405  PMID: 23285274
24.  Adversity and Syndemic Production Among Men Participating in the Multicenter AIDS Cohort Study: A Life-Course Approach 
Objectives
We tested a theory of syndemic production among men who have sex with men (MSM) using data from a large cohort study.
Methods
Participants were 1551 men from the Multicenter AIDS Cohort Study enrolled at 4 study sites: Baltimore, Maryland–Washington, DC; Chicago, Illinois; Los Angeles, California; and Pittsburgh, Pennsylvania. Participants who attended semiannual visits from April 1, 2008, to March 31, 2009, completed an additional survey that captured data about events throughout their life course thought to be related to syndemic production.
Results
Using multivariate analysis, we found that the majority of life-course predictor variables (e.g., victimization, internalized homophobia) were significantly associated with both the syndemic condition and the component psychosocial health outcomes (depressive symptoms, stress, stimulant use, sexual compulsivity, intimate partner violence). A nested negative binomial analysis showed that the overall life course significantly explained variability in the syndemic outcomes (χ2 = 247.94; P < .001; df = 22).
Conclusions
We identified life-course events and conditions related to syndemic production that may help to inform innovative interventions that will effectively disentangle interconnecting health problems and promote health among MSM.
doi:10.2105/AJPH.2012.300810
PMCID: PMC3518355  PMID: 23153154
25.  A Population-Based Study on Alcohol and High-Risk Sexual Behaviors in Botswana 
PLoS Medicine  2006;3(10):e392.
Background
In Botswana, an estimated 24% of adults ages 15–49 years are infected with HIV. While alcohol use is strongly associated with HIV infection in Africa, few population-based studies have characterized the association of alcohol use with specific high-risk sexual behaviors.
Methods and Findings
We conducted a cross-sectional, population-based study of 1,268 adults from five districts in Botswana using a stratified two-stage probability sample design. Multivariate logistic regression was used to assess correlates of heavy alcohol consumption (>14 drinks/week for women, and >21 drinks/week for men) as a dependent variable. We also assessed gender-specific associations between alcohol use as a primary independent variable (categorized as none, moderate, problem and heavy drinking) and several risky sex outcomes including: (a) having unprotected sex with a nonmonogamous partner; (b) having multiple sexual partners; and (c) paying for or selling sex in exchange for money or other resources. Criteria for heavy drinking were met by 31% of men and 17% of women. Adjusted correlates of heavy alcohol use included male gender, intergenerational relationships (age gap ≥10 y), higher education, and living with a sexual partner. Among men, heavy alcohol use was associated with higher odds of all risky sex outcomes examined, including unprotected sex (AOR = 3.48; 95% confidence interval [CI], 1.65 to 7.32), multiple partners (AOR = 3.08; 95% CI, 1.95 to 4.87), and paying for sex (AOR = 3.65; 95% CI, 2.58 to 12.37). Similarly, among women, heavy alcohol consumption was associated with higher odds of unprotected sex (AOR = 3.28; 95% CI, 1.71 to 6.28), multiple partners (AOR = 3.05; 95% CI, 1.83 to 5.07), and selling sex (AOR = 8.50; 95% CI, 3.41 to 21.18). A dose-response relationship was seen between alcohol use and risky sexual behaviors, with moderate drinkers at lower risk than both problem and heavy drinkers.
Conclusions
Alcohol use is associated with multiple risks for HIV transmission among both men and women. The findings of this study underscore the need to integrate alcohol abuse and HIV prevention efforts in Botswana and elsewhere.
Alcohol use is associated with multiple risks for HIV transmission in men and women. The findings underscore the need to integrate alcohol abuse and HIV prevention efforts in Botswana and elsewhere.
Editors' Summary
Background.
Human immunodeficiency virus (HIV), the cause of acquired immunodeficiency syndrome (AIDS), is most commonly spread through unprotected sex with an infected partner. HIV enters the body through the lining of the sex organs, rectum, or mouth, and destroys immune system cells, leaving the infected person susceptible to other viruses and bacteria. Although HIV education and prevention campaigns emphasize the importance of safe sex in reducing HIV transmission, people continue to become infected by having unprotected sex (that is, not using a condom) with either a nonmonogamous partner or multiple sexual partners, or in situations where they are paying for or selling sex. Research in different populations suggested that heavy alcohol use is associated with risky sexual behaviors. This is because alcohol relaxes the brain and body, reduces inhibitions, and diminishes risk perception. Drinking alcohol may further increase the risk of becoming infected with HIV through its suppressive effects on the immune system.
Why Was This Study Done?
Alcohol abuse is widespread in sub-Saharan Africa where most HIV infections occur and has been associated with risky sexual behaviors. It may therefore be one of the most common, potentially modifiable HIV risk factors in this region. However, research to date has concentrated on the association between alcohol consumption and risky sex in people attending HIV-treatment clinics or recruited at beer halls, and these populations may not be representative of the general population of sub-Saharan Africa. In this study, the researchers have investigated the potential role of alcohol in perpetuating the HIV epidemic by undertaking a population-based study on alcohol use and high-risk sexual behaviors in Botswana. Nearly a quarter of adults are infected with HIV here, and alcohol abuse is also common, particularly in the townships.
What Did the Researchers Do and Find?
The researchers recruited a random cross-section of people from the five districts of Botswana with the highest number of HIV-infected individuals and interviewed all 1,268 participants using a questionnaire. This included general questions about the participants (for example, their age and marital status) and questions about alcohol use, sexual behavior, and knowledge of HIV. Overall, 31% of the men in the study and 17% of the women were heavy drinkers—more than 21 drinks/week for men, 14 for women; a drink is half a pint of beer or a glass of wine. Heavy alcohol use was associated with being male, being in an intergenerational relationship (at least 10 years age difference between partners; intergenerational sex facilitates the continued spread of HIV in sub-Saharan Africa), having had more education, and living with a sexual partner. Among men, those who drank heavily were three to four times more likely to have unprotected sex or multiple partners or to pay for sex than nondrinkers. Among women, there was a similar association between heavy drinking and having unprotected sex or multiple partners, and heavy drinkers were eight times as likely to sell sex as nondrinkers. For both men and women, the more they drank, the more likely they were to have risky sex. The study did not address behavior among same-sex partnerships.
What Do These Findings Mean?
This study indicates that heavy alcohol consumption is strongly and consistently associated with sexual risk behaviors in both men and women in Botswana. Because of the study design, it does not prove that heavy alcohol use is the cause of such behaviors but provides strong circumstantial evidence that this is the case. It is possible that these results may not apply to neighboring African countries—Botswana is unique in being relatively wealthy and in its government being strongly committed to tackling HIV. Nevertheless, taken together with the results of other studies, this research strongly argues for the need to deal with alcohol abuse within HIV prevention programs in sub-Saharan Africa. Strategies to do this could include education campaigns that target both alcohol use and HIV in schools and in social venues, including beer halls. But, stress the researchers, any strategy that is used must consider the cultural and social significance of alcohol use (in Botswana, alcohol use is a symbol of masculinity and high socioeconomic status) and must simultaneously tackle not only the overlap between alcohol use and risky sexual behavior but also the overlap between alcohol and other risk behaviors such as intergenerational sex.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030392.
US National Institute of Allergy and Infectious Diseases factsheet on HIV infection and AIDS
US Department of Health and Human Services information on AIDS
US Centers for Disease Control and Prevention information on HIV/AIDS
US National Institute on Alcohol Abuse and Alcoholism patient information on alcohol and HIV/AIDS]
Aidsmap, information on HIV and AIDS provided by the charity NAM,which includes some information on HIV infections and alcohol
AVERT information on HIV and AIDS in Botswana
doi:10.1371/journal.pmed.0030392
PMCID: PMC1592342  PMID: 17032060

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