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1.  Correlates of amphetamine-type stimulants use and associations with HIV-related risks among young women engaged in sex work in Phnom Penh, Cambodia 
Drug and alcohol dependence  2011;120(1-3):119-126.
Amphetamine-type stimulant (ATS) use has increased in Cambodia and emerged as a significant problem among female sex workers (FSWs), potentially contributing to increased risk of HIV. We examined the prevalence of ATS use and its effect on sexual risk behaviors, and sexually transmitted infections (STI) among FSWs in Phnom Penh, Cambodia.
A one-year prospective study among young women engaged in sex work in brothels, entertainment establishments and on a freelance basis. Socio-demographics, sexual risks, and recent ATS use were assessed by self-report. Blood and urine samples were collected to detect HIV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC). Bivariate and multivariate longitudinal analyses were conducted to assess the effects of ATS use on number of sex partners, inconsistent condom use with paying partners and incident STI.
ATS use was higher among women working freelance (35.6%) and in brothels (34.8%) compared to women working in entertainment establishments (17.7%) or in multiple venues (14.8%). ATS users reported more sex partners and days drunk in the previous month. In multivariate longitudinal analysis, ATS use was associated with having a higher number of sex partners (Adjusted Risk Ratio 1.49; 95% CI: 1.00–2.21) and incident STI (Adjusted Odds Ratio 5.41; 95% CI: 1.15–25.48), but not inconsistent condom use with paying partner.
ATS users had more sex partners, high level of alcohol use, and were at increased risk of STI. Our findings underscore ATS use as an important emerging risk exposure that should be integrated into HIV prevention interventions targeting this population.
PMCID: PMC3226861  PMID: 21820251
mphetamine-type stimulant; HIV/STI; Female sex workers; Cambodia; Risk behaviors
2.  Epidemiology of HPV genotypes in Uganda and the role of the current preventive vaccines: A systematic review 
Limited data are available on the distribution of human papillomavirus (HPV) genotypes in the general population and in invasive cervical cancer (ICC) in Uganda. Yet, with the advent of preventive HPV vaccines that target HPV 16 and 18 responsible for causing about 70% of ICC cases in the world, such information is crucial to predict how vaccination and HPV-based screening will influence prevention of ICC.
To review the distribution of HPV infection and prevalent genotypes, electronic databases (e.g. PubMed/MEDLINE and HINARI) were searched for peer reviewed English articles on HPV infection up to November 30, 2010. Eligible studies were selected according to the following criteria: DNA-confirmed cervical or male genital HPV prevalence and genotypes, HPV incidence estimates and HPV seroprevalence among participants.
Twenty studies were included in the review. Among HIV negative adult women, the prevalence of HR-HPV infections ranged from 10.2% -40.0% compared to 37.0% -100.0% among HIV positive women. Among HIV positive young women aged below 25 years, the prevalence of HR-HPV genotypes ranged from 41.6% -75.0% compared to 23.7% -67.1% among HIV negative women. Multiple infections with non vaccine HR-HPV genotypes were frequent in both HIV positive and HIV negative women. The main risk factors for prevalent HPV infections were age, lifetime number of sexual partners and HIV infection. Incident infections with HR-HPV genotypes were more frequent among adult HIV positive than HIV negative women estimated at 17.3 and 7.0 per 100 person-years, respectively. Similarly, incident HR-HPV among young women aged below 25 years were more frequent among HIV positive (40.0 per 100 person-years) than HIV negative women (20.3 per 100 person-years) women. The main risk factor for incident infection was HIV infection. HPV 16 and 18 were the most common genotypes in ICC with HPV 16/18 contributing up to 73.5% of cases with single infections.
Among uncircumcised adult HIV positive males, HR-HPV prevalence ranged from 55.3% -76.6% compared to 38.6% -47.6% in HIV negative males. Incident and multiple HR-HPV infections were frequent in HIV positive males. Being uncircumcised was the main risk factor for both prevalent and incident HPV infection.
Infections with HR-HPV genotypes were very common particularly among HIV positive individuals and young women irrespective of HIV status. Given the high prevalence of HIV infection, HPV-associated conditions represent a major public health burden in Uganda. However, although the most common HPV genotypes in ICC cases in Uganda were those targeted by current preventive vaccines, there were a large number of individuals infected with other HR-HPV genotypes. Technology allowing, these other HR-HPV types should be considered in the development of the next generation of vaccines.
PMCID: PMC3163594  PMID: 21749691
3.  Sex-Specific Immunization for Sexually Transmitted Infections Such as Human Papillomavirus: Insights from Mathematical Models 
PLoS Medicine  2011;8(12):e1001147.
Johannes Bogaards and colleagues use mathematical models to investigate whether vaccinating females only, males only, or both sexes is the best way to achieve the most effective reduction in the population prevalence of sexually-transmitted infections
Sex-specific differences regarding the transmissibility and the course of infection are the rule rather than the exception in the epidemiology of sexually transmitted infections (STIs). Human papillomavirus (HPV) provides an example: disease outcomes differ between men and women, as does the potential for transmission to the opposite sex. HPV vaccination of preadolescent girls was recently introduced in many countries, and inclusion of boys in the vaccination programs is being discussed. Here, we address the question of whether vaccinating females only, males only, or both sexes is the most effective strategy to reduce the population prevalence of an STI like HPV.
Methods and Findings
We use a range of two-sex transmission models with varying detail to identify general criteria for allocating a prophylactic vaccine between both sexes. The most effective reduction in the population prevalence of infection is always achieved by single-sex vaccination; vaccinating the sex with the highest prevaccine prevalence is the preferred strategy in most circumstances. Exceptions arise only when the higher prevaccine prevalence is due to a substantially lower rate of natural immunity, or when natural immunity is lifelong, and a prolonged duration of infectiousness coincides with increased transmissibility. Predictions from simple models were confirmed in simulations based on an elaborate HPV transmission model. Our analysis suggests that relatively inefficient genital transmission from males to females might render male vaccination more effective in reducing overall infection levels. However, most existing HPV vaccination programs have achieved sufficient coverage to continue with female-only vaccination.
Increasing vaccine uptake among preadolescent girls is more effective in reducing HPV infection than including boys in existing vaccination programs. As a rule, directing prophylactic immunization at the sex with the highest prevaccine prevalence results in the largest reduction of the population prevalence.
Please see later in the article for the Editors' Summary
Editors' Summary
About 10% of cancers in women occur in the cervix, the structure that connects the womb to the vagina. Every year, more than a quarter of a million women (85% of them in developing countries) die because of cervical cancer, which only occurs after the cervix has been infected with a human papillomavirus (HPV) through sexual intercourse (HPV is one of more than thirty sexually transmissable organisms that, globally, cause many millions of sexually transmitted infections every year). There are many types of HPV, a virus that infects the skin and the mucosa (the moist membranes that line various parts of the body, including the cervix). Most people become infected with HPV at some time during their life, but most never know they have been infected. Some HPV types cause harmless warts on the skin or around the genital area, and several—in particular HPV16 and HPV18, so-called high-risk HPVs—can cause cervical cancer (and some other cancers, including anal, penile, head, and neck cancers). HPV infections are usually cleared by the immune system, but about 10% of women infected with a high-risk HPV develop a long-term infection that puts them at risk of developing cervical cancer.
Why Was This Study Done?
Screening programs have greatly reduced cervical cancer deaths in developed countries by detecting the cancer early, when it can be treated. However, it would be better to prevent cervical cancer ever developing. Moreover, most women in developing countries do not have access to screening. Because infection with specific HPV types can cause the development of some types of cervical cancer, vaccination of girls against HPV before the onset of sexual activity might be one way to prevent cervical cancer. Scientists recently developed a vaccine that prevents infection with HPV16 and HPV18, and HPV vaccination programs have been introduced in several countries. These programs are currently directed only at girls because HPV-related illness and death are higher among women than men, but should boys also be included in HPV vaccination programs? Men would benefit directly from immunization against HPV-related diseases, but, in addition, vaccination of boys might help to reduce the circulation of HPV in the population, thereby indirectly improving the protection of women through so-called “herd immunity.” In this study, the researchers used mathematical models to investigate whether vaccinating girls only, boys only, or both sexes is the most effective way to reduce the population prevalence of HPV infection (the proportion of the population infected with HPV).
What Did the Researchers Do and Find?
The researchers first used a range of standard two-sex mathematical models of infection and transmission in heterosexual populations to identify general criteria for allocating an HPV vaccine between the sexes. They found that the most effective reduction in the population prevalence of HPV infection was always achieved by single-sex vaccination and that, in most situations, the preferred strategy was to vaccinate the sex with the highest prevaccine prevalence of HPV infection. The researchers confirmed these predictions using a more elaborate HPV transmission model that incorporated differences among individuals in age and level of sexual activity. Importantly, this second analysis also suggested that for existing girl-only vaccination programs, increasing coverage of vaccination among girls would bolster herd immunity more effectively than switching to a policy of vaccinating both sexes.
What Do These Findings Mean?
The findings of this study suggest that increasing vaccine uptake among preadolescent girls is a more effective way to reduce HPV infection than including boys in existing vaccination programs. They also suggest that directing HPV vaccination at the sex with the highest prevaccine prevalence of infection will reduce the population prevalence of HPV most effectively. Although the accuracy of these findings is dependent on the assumptions included in the mathematical transmission models used by the researchers, these findings support a policy of increasing female HPV vaccine coverage as far as possible, within the limits set by vaccine acceptance and economic constraints. More generally, these findings suggest that single-sex preventative interventions might be the best way to reduce heterosexual transmission of other sexually transmitted infections and that targeting the sex with the highest prevalence of infection might achieve the most effective reduction in the population prevalence of these common diseases.
Additional Information
Please access these websites via the online version of this summary at
The US National Cancer Institute provides information about cervical cancer for patients and for health professionals, including information on HPV vaccines (in English and Spanish)
The US Centers for Disease Control and Prevention also has information about cervical cancer and HPV
The UK National Health Service Choices website has pages on cervical cancer and HPV vaccination (available in several languages and including a short video of girls talking about HPV vaccination)
The PREHDICT project investigates health-economic modeling of prevention strategies for HPV-related diseases in European countries; information about this project is available from the European Cervical Cancer Association
More information about cervical cancer and HPV vaccination is available from Macmillan Cancer Support
Personal stories about cervical cancer are available through the charity Healthtalkonline
MedlinePlus provides links to additional resources about cervical cancer and other sexually transmitted infections (in English and Spanish)
PMCID: PMC3243713  PMID: 22205887
4.  Epidemiology of HPV Genotypes among HIV Positive Women in Kenya: A Systematic Review and Meta-Analysis 
PLoS ONE  2016;11(10):e0163965.
There is a scarcity of data on the distribution of human papillomavirus (HPV) genotypes in the HIV positive population and in invasive cervical cancer (ICC) in Kenya. This may be different from genotypes found in abnormal cytology. Yet, with the advent of preventive HPV vaccines that target HPV 16 and 18, and the nonavalent vaccine targeting 90% of all ICC cases, such HPV genotype distribution data are indispensable for predicting the impact of vaccination and HPV screening on prevention. Even with a successful vaccination program, vaccinated women will still require screening to detect those who will develop ICC from other High risk (HR) HPV genotypes not prevented by current vaccines. The aim of this review is to report on the prevalence of pHR/HR HPV types and multiple pHR/HR HPV genotypes in Kenya among HIV positive women with normal, abnormal cytology and ICC.
PUBMED, EMBASE, SCOPUS, and PROQUEST were searched for articles on HPV infection up to August 2nd 2016. Search terms were HIV, HPV, Cervical Cancer, Incidence or Prevalence, and Kenya.
The 13 studies included yielded a total of 2116 HIV-infected women, of which 89 had ICC. The overall prevalence of pHR/HR HPV genotypes among HIV-infected women was 64% (95%CI: 50%-77%). There was a borderline significant difference in the prevalence of pHR/HR HPV genotypes between Female Sex workers (FSW) compared to non-FSW in women with both normal and abnormal cytology. Multiple pHR/HR HPV genotypes were highly prominent in both normal cytology/HSIL and ICC. The most prevalent HR HPV genotypes in women with abnormal cytology were HPV 16 with 26%, (95%CI: 23.0%-30.0%) followed by HPV 35 and 52, with 21% (95%CI: 18%-25%) and 18% (95%CI: 15%-21%), respectively. In women with ICC, the most prevalent HPV genotypes were HPV 16 (37%; 95%CI: 28%-47%) and HPV 18 (24%; 95%CI: 16%-33%).
HPV 16/18 gains prominence as the severity of cervical disease increases, with HPV 16/18 accounting for 61% (95%CI: 50.0%-70.0%) of all ICC cases. A secondary prevention program will be necessary as this population harbors multiple pHR/HR HPV co-infections, which may not be covered by current vaccines. A triage based on FSW as an indicator may be warranted.
PMCID: PMC5072621  PMID: 27764092
5.  Sex work and HIV in Cambodia: trajectories of risk and disease in two cohorts of high-risk young women in Phnom Penh, Cambodia 
BMJ Open  2013;3(9):e003095.
HIV prevalence among Cambodian female sex workers (FSW) is among the highest in Southeast Asia. We describe HIV prevalence and associated risk exposures in FSW sampled serially in Phnom Penh, Cambodia (Young Women's Health Study (YWHS)), before and after the implementation of a new law designed to combat human trafficking and sexual exploitation.
Cross-sectional analysis of baseline data from two prospective cohorts.
Community-based study in Phnom Penh, Cambodia.
Women aged 15–29 years, reporting ≥2 sexual partners in the last month and/or engaged in transactional sex in the last 3 months, were enrolled in the studies in 2007 (N=161; YWHS-1), and 2009 (N=220; YWHS-2) following information sessions where 285 and 345 women attended.
Primary outcomes
HIV prevalence, sexual risk behaviour, amphetamine-type stimulant (ATS) and alcohol use, and work-related factors were compared in the two groups, enrolled before and after implementation of the new law.
Participants in the two cohorts were similar in age (median 25 years), but YWHS-2 women reported fewer sex partners, more alcohol use and less ATS use. A higher proportion of YWHS-2 compared with YWHS-1 women worked in entertainment-based venues (68% vs 31%, respectively). HIV prevalence was significantly lower in the more recently sampled women: 9.2% (95% CI 4.5% to 13.8%) vs 23% (95% CI 16.5% to 29.7%).
Sex work context and risk have shifted among young FSW in Phnom Penh, following implementation of anti-prostitution and anti-trafficking laws. While both cohorts were recruited using the same eligibility criteria, more recently sampled women had lower prevalence of sexual risk and HIV infection. Women engaging more directly in transactional sex have become harder to sample and access. Future prevention research and programmes need to consider how new policies and demographic changes in FSW impact HIV transmission.
PMCID: PMC3773643  PMID: 24022389
6.  Prevalence and Molecular Epidemiology of Human Papillomavirus Infection in Italian Women with Cervical Cytological Abnormalities 
Human papillomavirus (HPV) infection is the most common sexually transmitted infection and high-risk HPV types are a necessary cause for the development of cervical cancer. The present study investigated the HPV-type specific prevalence in 650 women, aged 15-76 years, with cytological abnormalities and the association between HPV infection and cervical disease in a subset of 160 women for whom cytological results for Pap-Test were available, during the period 2008-2011 in Cagliari (Southern Italy).
Design and Methods
HPV-DNA extraction was performed by lysis and digestion with proteinase K and it was typed by using the INNOLiPA HPV Genotyping Assay.
Overall the HPV prevalence was 52.6%; high-risk genotypes were found in 68.9% of women and multiple-type infection in 36.1% of HPV-positive women. The commonest types were HPV-52 (23.4%), HPV-53 (15.7%), HPV-16 (15.4%) and HPV-6 (12.4%). Among the women with cytological diagnosis, any-type of HPV DNA was found in 49.4% of the samples and out of these 93.7% were high-risk genotypes. Genotype HPV 53 was the commonest type among women affected by ASCUS lesions (21.4%), genotype 52 in positive L-SIL cases (22.5%), genotype 16 H-SIL (27.3%).
This study confirmed the high prevalence of HPV infection and high-risk genotypes among women with cervical abnormalities while, unlike previously published data, genotype HPV-52 was the most common type in our series. These data may contribute to increase the knowledge of HPV epidemiology and designing adequate vaccination strategies.
Significance for public healthHuman papillomavirus (HPV) is the most common sexually-transmitted agent, which can cause cervical lesions and cancer in females. Efforts to reduce the burden of cervical cancer with cytology screening in the last years have had limited success. HPV infection and disease imposes a substantial burden of direct costs on the Italian National Health Service that have never been fully quantified. Monitoring HPV prevalence could represent a tool to follow the evolution of the infection in the vaccination and post-vaccination era, to understand the impact of HPV types in cervical diseases in Italy. Our survey shows an high frequency of infections sustained by HPV 52. Given the recent implementation of a widespread immunization program with vaccines not containing HPV 52, it has been relevant to prove the high prevalence of this HPV genotype from the beginning of the vaccination campaign, to avoid ascribing to the vaccination program a possible selection effect and the importance of non-vaccine HPV types in the burden of cervical disease, in order to assess the opportunity to realize new vaccine including other types.
PMCID: PMC4140382  PMID: 25170506
HPV epidemiology; cervical abnormalities; HPV prevalence
7.  The Need for Cervical Cancer Control in HIV-Positive and HIV-Negative Women from Romania by Primary Prevention and by Early Detection Using Clinically Validated HPV/DNA Tests 
PLoS ONE  2015;10(7):e0132271.
In Romania, a country with no organized national surveillance program regarding cervical cancer, the early diagnosis of HPV (Human Papilloma Virus) infections is a major requirement, especially in HIV-infected women. The objective of this study was to determine the HPV prevalence and type distribution in young HIV-positive women and to assess the difference in the risk factors for developing cervical cancer compared to those of HIV-negative women.
We conducted one cross-sectional cohort study from June 2013–September 2014, including 1,032 women: 992 HIV- women who were 36.5 years old (limits: 17 ÷ 84) and 40 HIV + women who were 22.9 years old (limits: 17 ÷ 30) with iatrogenic HIV infected. We detected HPV types with the Linear Array HPV Genotyping test (Roche, Romania).
DNA/HPV was detected in 18/40 (45%) of the HIV+ patients and in 350/992 (35.2%) of the HIV- patients (OR = 1.5, 95%CI 0.76÷2.96). After age adjustment, the overall HPV prevalence was 51.6% in HIV+ versus 63.2% in HIV- women aged under 25, and 22.2% in HPV+ versus 47.2% in HIV- women aged 25–34. We detect HIV being a risk factor for acquiring multiple HPV type infections (OR = 2.30, 95% CI 0.88÷5.97). The eight most common HPV types (high-risk, and low-risk) for women below age 30, HIV+ / - were: HPV 16, 18, 31, 51, 58, 68, and 6 and 82 respectively. To assess the risk factors of HIV-positive women for acquiring HPV infection, we analyzed the CD4/μL, ARN/HIV copies/μL, the age group, the number of sexual partners, smoking, and the type of HPV infection (single versus multiple infections). We found that the number of sexual partners and smoking are statistically significant risk factors.
Even though there are no significant differences regarding the prevalence of HPV infection in HIV + versus HIV – patients, multiple infections were more frequent in the first group. In our study group young HIV-infected patients under HAART therapy, high number of sexual partners (more than 3) and smoking were detected to be risk factors. Future organized screening for HPV infection using sensitive and specific methods are necessary at the national level in Romania.
PMCID: PMC4506070  PMID: 26186361
8.  HPV Genotype Distribution in Cervical Intraepithelial Neoplasia among HIV-Infected Women in Pune, India 
PLoS ONE  2012;7(6):e38731.
The distribution of HPV genotypes, their association with rigorously confirmed cervical precancer endpoints, and factors associated with HPV infection have not been previously documented among HIV-infected women in India. We conducted an observational study to expand this evidence base in this population at high risk of cervical cancer.
HIV-infected women (N = 278) in Pune, India underwent HPV genotyping by Linear Array assay. Cervical intraepithelial neoplasia (CIN) disease ascertainment was maximized by detailed assessment using cytology, colposcopy, and histopathology and a composite endpoint.
CIN2+ was detected in 11.2% while CIN3 was present in 4.7% participants. HPV genotypes were present in 52.5% (146/278) and ‘carcinogenic’ HPV genotypes were present in 35.3% (98/278) HIV-infected women. ‘Possibly carcinogenic’ and ‘non/unknown carcinogenic’ HPV genotypes were present in 14.7% and 29.5% participants respectively. Multiple (≥2) HPV genotypes were present in half (50.7%) of women with HPV, while multiple ‘carcinogenic’ HPV genotypes were present in just over a quarter (27.8%) of women with ‘carcinogenic’ HPV. HPV16 was the commonest genotype, present in 12% overall, as well as in 47% and 50% in CIN2+ and CIN3 lesions with a single carcinogenic HPV infection, respectively. The carcinogenic HPV genotypes in declining order of prevalence overall included HPV 16, 56, 18, 39, 35, 51, 31, 59, 33, 58, 68, 45 and 52. Factors independently associated with ‘carcinogenic’ HPV type detection were reporting ≥2 lifetime sexual partners and having lower CD4+ count. HPV16 detection was associated with lower CD4+ cell counts and currently receiving combination antiretroviral therapy.
HPV16 was the most common HPV genotype, although a wide diversity and high multiplicity of HPV genotypes was observed. Type-specific attribution of carcinogenic HPV genotypes in CIN3 lesions in HIV-infected women, and etiologic significance of concurrently present non/unknown carcinogenic HPV genotypes await larger studies.
PMCID: PMC3378535  PMID: 22723879
9.  Distribution of human papillomaviruses and bacterial vaginosis in HIV positive women with abnormal cytology in Mombasa, Kenya 
HPV is the major etiological factor in the causal pathway for cervical cancer, which is the leading cancer among women in sub-Saharan Africa. HIV is associated with a higher prevalence and a broader range of high-risk HPV genotypes. Studies have shown a positive association between Bacterial vaginosis (BV) and HPV and HIV. Also, in African women, BV was found to be significantly associated with vaginal inflammation. The high prevalence of BV, HIV and HPV infections in the African continent makes elucidation of the interactions with one another of utmost public health interest. The aims of the current study are to examine the frequency of HPV genotypes and BV as well as their respective risk factors within an HIV infected population with abnormal cytology in the resource-constrained setting of Mombasa, Kenya and, secondly, highlight issues to consider for triple co-infection clinical management.
Cross-sectional analysis with a sample drawn from an ongoing cohort study. All consenting, non-pregnant HIV infected women, between 18 and 50 years of age, without a history of cervical cancer or hysterectomy, between November 2005 and April 2006 were screened for HR HPV DNA in Mombasa, Kenya. 1 out of 4 HIV positive women fulfilled the criteria by having SIL (24.9 %). 600 HIV infected women were tested to reach a cohort of 74 HIV women with abnormal cytology. To assess which factors were associated with HR HPV, crude statistical analysis was performed through logistic regression.
Bacterial vaginosis (BV) was found in 46 women out of 74 (62.2 %). Cervicitis was diagnosed in 15 % of women (n = 11), of which 8 had BV. The most prevalent HPV genotypes were HPV 16 (33.8), HPV 53 (24.3) and HPV 18 (17.6 %), while 65 % of the participants had multiple genotype infection.
Statistically significant associations between CD4 counts <200 cells/μl and multiple HPV prevalence, adjusted for age were also noted (OR = 3.7; 95 CI: 1.2–12.1; p = 0.03) and HPV53 (OR = 4.4, 95 % CI: 1.4–13.6; p = 0.01). A statistically significant association was found between CD4 count ≥ 350 μl and HPV 16 adjusted for age (OR = 2.9; 95 % CI: 1.0- 8.3; p = 0.05). A borderline statistically significant association was observed between BV and HPV58 (crude OR = 4.1, 95 % CI: 0.8–21.0; p = 0.07).
The most prevalent HPV genotypes observed were HPV 16, HPV 53, and HPV 18, which have a combined prevalence of 76 %. Our results show that a triage based on CD4 count should start at CD4 count ≥ 350 μl as our study suggests that HPV 16 are more prevalent when women are moderately immunosuppressed. Given the high prevalence of HPV 53 in a HIV infected population with abnormal cytology, its cervical carcinoma genesis potential as a stand-alone genotype and as well as its synergism with multiple infections should be investigated. The new WHO guideline in resource-poor settings to rescreen women for HPV within ten years may be more effective if BV and cervicitis management become a major component for HIV-HPV management.
PMCID: PMC4822250  PMID: 27053945
HIV; HPV; CD4 count; BV; Cervicitis
10.  Cervical human papillomavirus infection among female sex workers in southern Vietnam 
Cervical cancer is the most frequently diagnosed malignancy among women in southern Vietnam where its incidence is one of the highest observed worldwide.
Cervical HPV DNA infection was measured in a cross-sectional sample of 282 female sex workers (FSW) in Soc Trang province in southern Vietnam. HPV DNA was detected in 85% of FSW and prevalence did not vary by age. Thirty-five HPV genotypes were detected; HPV 52 was the most common type. Half of HPV-positive women were infected with oncogenic types and 37% were infected with multiple genotypes. The prevalence of oncogenic HPV infection was lower among FSW with more formal education (adj. prevalence ratio = 0.63, 95% CI 0.42–0.93), those servicing 25 or more clients per month (adj. PR = 0.66 95% CI 0.48–0.92), and those engaging in withdrawal prior to ejaculation (adj. PR = 0.68, 95% CI 0.53–0.87). Oncogenic HPV prevalence was higher among FSW with regular male partners who had other female partners (adj. PR = 1.75, 95% CI 1.34–2.28) and FSW who were HIV+ (adj. PR = 1.42, 95% CI 1.08–1.88).
Our results demonstrate that although cervical HPV infection is extremely common among FSW in southern Vietnam, prevalence varies by education level, sexual activity, habits of regular partners, and HIV status.
PMCID: PMC2405771  PMID: 18433504
11.  Factors Affecting the Prevalence of Strongly and Weakly Carcinogenic and Lower-Risk Human Papillomaviruses in Anal Specimens in a Cohort of Men Who Have Sex with Men (MSM) 
PLoS ONE  2013;8(11):e79492.
MSM are at higher risk for invasive anal cancer. Twelve human papillomaviruses (HPVs) cause cervical cancer in women (Group 1 high-risk HPVs (hrHPVs)) and 13 HPVs are probable/possible causes (Group 2 hrHPVs) of cervical malignancy. HPVs rarely associated with malignancy are classified as lower-risk HPVs (lrHPVs).
Materials and Methods
Dacron-swab anal-cytology specimens were collected from and data complete for 97% (1262/1296) of Multicenter AIDS Cohort Study (MACS) men tested for HPVs using the Linear Array assay. Multivariate Poisson regression analyses estimated adjusted prevalence ratios for Group 1/2 hrHPVs and lrHPVs, controlling for the effects of age, race, ethnicity, sexual partnerships, smoking; HIV-infection characteristics, treatment, and immune status among HIV-infected men.
HIV-infected men showed 35–90% higher prevalence of Group 1/2 hrHPVs and lrHPVs than HIV-uninfected men, and higher prevalence of multi-Type, and multiple risk-group infections. CD4+ T-cell count was inversely associated with HPV Group 2 prevalence (p<0.0001). The number of receptive anal intercourse (RAI) partners reported in the 24 months preceding HPV testing predicted higher prevalence of Group 1/2 hrHPVs. Men reporting ≥30 lifetime male sex partners before their first MACS visit and men reporting ≥1 RAI partners during the 24 months before HPV testing showed 17–24% and 13–17% higher prevalence of lrHPVs (p-values ≤0.05). Men reporting smoking between MACS visit 1 and 24 months before HPV testing showed 1.2-fold higher prevalence of Group 2 hrHPVs (p = 0.03). Both complete adherence to CART (p = 0.02) and HIV load <50 copies/mL (p = 0.04) were protective for Group 1 hrHPVs among HIV-infected men.
HIV-infected men more often show multi-type and multi-group HPV infections HIV-uninfected men. Long-term mutual monogamy and smoking cessation, generally, and CART-adherence that promotes (HIV) viremia control and prevents immunosuppression, specifically among HIV-infected MSM, are important prevention strategies for HPV infections that are relevant to anal cancer.
PMCID: PMC3835810  PMID: 24278140
12.  Cervical HPV Infection in Female Sex Workers: A Global Perspective 
The Open AIDS Journal  2013;7:58-66.
Approximately 291 million women worldwide are HPV DNA carriers. Studies have indicated that having multiple sexual partners may lead to higher HPV transmission. Thus female sex workers (FSWs) may be at greater risk of infection compared to the general population. Herein we review publications with data on FSW cervical HPV test results. We also examine variations of HPV prevalence and risk behaviors by region. Knowledge of prevalent HPV types in FSWs may lead to improved prevention measures and assist in understanding vaccination in high-risk groups.
We conducted a review of the literature by searching PUBMED using the terms “prostitution” or “female sex workers”, “human papillomavirus” or “HPV”, and “prevalence” or “PCR” to find articles. We excluded studies without HPV testing or HPV type specific results, or unconventional HPV testing.
A total of 35 peer-reviewed publications were included in our review. High risk HPV types 16 and 18 ranged from 1.1-38.9‰ in prevalence. In addition to high-risk HPV types, newer studies reported non-carcinogenic HPV types also of high prevalence. The most prevalent HPV types reported among FSWs included HPV 6 (11.5%), 16 (38.9%), 18 (23.1%), 31 (28.4%), 52 (32.7%), and 58 (26.0%).
Female sex workers have an overall high prevalence of HPV infection of high-risk types as evident through various testing methods. FSWs are thought to be at increased risk of cervical cancer because of high HPV exposure. This highlights the need for HPV and cervical prevention campaigns tailored to FSWs.
PMCID: PMC3915319  PMID: 24511334
Female sex workers; genotype; HPV; PCR; prevalence; prostitution.
13.  HIV associated high-risk HPV infection among Nigerian women 
BMC Infectious Diseases  2013;13:521.
In developed countries, the incidence of cervical cancer has remained stable in HIV+ women but the prevalence and multiplicity of high-risk HPV (hrHPV) infection, a necessary cause of cervical cancer, appears different comparing HIV+ to HIV- women. Little is known about HIV and HPV co-infection in Africa.
We enrolled women presenting at our cervical cancer screening program in Abuja, Nigeria between April and August 2012, and collected information on demographic characteristics, risk factors of HPV infection and samples of exfoliated cervical cells. We used Roche Linear Array HPV Genotyping Test® to characterize prevalent HPV and logistic regression models to estimate the association between HIV and the risk of hrHPV infection.
There were 278 participants, 54% (151) were HIV+, 40% (111) were HIV-, and 6% (16) had unknown HIV status. Of these, data from 149 HIV+ and 108 HIV- women were available for analysis. The mean ages (±SD) were 37.6 (±7.7) years for HIV+ and 36.6 (±7.9) years for HIV- women (p-value = 0.34). Among the HIV+ women, HPV35 (8.7%) and HPV56 (7.4%) were the most prevalent hrHPV, while HPV52 and HPV68 (2.8%, each) were the most prevalent hrHPV types among HIV- women. The multivariate prevalence ratio for any hrHPV and multiple hrHPV infections were 4.18 (95% CI 2.05 – 8.49, p-value <0.0001) and 6.6 (95% CI 1.49 – 29.64, p-value 0.01) respectively, comparing HIV + to HIV- women, adjusted for age, and educational level.
HIV infection was associated with increased risk of any HPV, hrHPV and multiple HPV infections. Oncogenic HPV types 35, 52, 56 and 68 may be more important risk factors for cervical pre-cancer and cancer among women in Africa. Polyvalent hrHPV vaccines meant for African populations should protect against other hrHPV types, in addition to 16 and 18.
PMCID: PMC3826514  PMID: 24192311
HIV; HPV; Nigeria
14.  The Prevalence and Risk Factors of Human Papillomavirus in Female Sex Workers 
Human papillomavirus virus (HPV) is the major causative factor for cervical cancer, and sex workers are at high risk for HPV infection. In this study, we aimed to estimate the prevalence and risk factors of HPV infection among female sex workers (FSWs).
Materials and Methods:
The study included 239 brothel-based FSWs who work in Izmir, Turkey. A self-administered questionnaire for risk factors was completed, and cervical brush samples were taken for HPV detection and typing. HPV detection and typing were performed by multiplex polymerase chain reaction (PCR) and reverse hybridization methods. The risk factors related to HPV infection were determined by multivariate analysis.
The prevalence of HPV among FSWs was 20.1%. HPV18 was the most common type (40%), followed by HPV16 (17%) and HPV50 (15%). Logistic regression analysis revealed that being less than 30 years of age, having a high frequency of sexual contacts, smoking, and lack of condom use were significantly associated with HPV infection.
FSWs have a high prevalence of HPV infection and are at increased risk for cervical cancer. As they are a priority group for active follow-up, national strategies for reducing HPV among FSWs and regular cervical cancer screening programs should be implemented for this population.
PMCID: PMC4261505  PMID: 25610243
Human papillomavirus; Sex workers
15.  Selling sex in unsafe spaces: sex work risk environments in Phnom Penh, Cambodia 
The risk environment framework provides a valuable but under-utilised heuristic for understanding environmental vulnerability to HIV and other sexually transmitted infections among female sex workers. Brothels have been shown to be safer than street-based sex work, with higher rates of consistent condom use and lower HIV prevalence. While entertainment venues are also assumed to be safer than street-based sex work, few studies have examined environmental influences on vulnerability to HIV in this context.
As part of the Young Women's Health Study, a prospective observational study of young women (15-29 years) engaged in sex work in Phnom Penh, we conducted in-depth interviews (n = 33) to explore vulnerability to HIV/STI and related harms. Interviews were conducted in Khmer by trained interviewers, transcribed and translated into English and analysed for thematic content.
The intensification of anti-prostitution and anti-trafficking efforts in Cambodia has increased the number of women working in entertainment venues and on the street. Our results confirm that street-based sex work places women at risk of HIV/STI infection and identify significant environmental risks related to entertainment-based sex work, including limited access to condoms and alcohol-related intoxication. Our data also indicate that exposure to violence and interactions with the police are mediated by the settings in which sex is sold. In particular, transacting sex in environments such as guest houses where there is little or no oversight in the form of peer or managerial support or protection, may increase vulnerability to HIV/STI.
Entertainment venues may also provide a high risk environment for sex work. Our results indicate that strategies designed to address HIV prevention among brothel-based FSWs in Cambodia have not translated well to street and entertainment-based sex work venues in which increasing numbers of women are working. There is an urgent need for targeted interventions, supported by legal and policy reforms, designed to reduce the environmental risks of sex work in these settings. Future research should seek to investigate sex work venues as risk environments, explore the role of different business models in mediating these environments, and identify and quantify exposure to risk in different occupational settings.
PMCID: PMC3339327  PMID: 22099449
sex work; risk; environment; vulnerability; HIV; STI; young women; entertainment; Cambodia
16.  Prevalence, Genotype Distribution and Risk Factors for Cervical Human Papillomavirus Infection in the Grand Tunis Region, Tunisia 
PLoS ONE  2016;11(6):e0157432.
Implementation of Human Papillomavirus (HPV) vaccination should be considered a key cervical cancer prevention strategy in Tunisia, where Pap smear screening is not efficient. This study aims to estimate the prevalence and to identify risk factors associated with HPV infection among women from Grand Tunis, Tunisia. We conducted a cross-sectional study, between December 2012 and May 2013. Eligible women for this study were those aged 18–65 years, sexually active, who sought medical attention at their primary health care centre or clinic in Grand Tunis, Tunisia and who gave written consent. A liquid-based Pap smear sample was obtained from all women using a cervical brush. Only women with betaglobin positive test were further analysed for HPV detection and typing. A nested-PCR of the L1 region was performed followed by reverse line blot hybridization to facilitate the specific detection of 31 HPV genotypes. Multiple logistic regression modeling was used for the analysis of associations between variables with some considered possible confounders after checking for interactions. A total of 391 women were enrolled in this study and 325 out of the 391 cervical samples were positive for the betaglobin test. Overall HPV prevalence was 13.2% [9.8%−17.5%], with the following most prevalent HPV genotypes: HPV6 (40%), HPV40 (14%), HPV16 (12%), HPV52 (9%), HPV31 and HPV59 (7%), followed by HPV68 (4%). Mean age of HPV positive women was 40.7±0.92 years. Independently associated risk factors of HPV infection were smoking (OR:2.8 [0.8–9.6]), low income (OR:9.6 [1.4–63.4), bad housing type (OR:2.5 [1–6.8]), partner with multiple sexual relationship (OR:4.5 [0.9–22.9]) and single women (widowed, divorced, separated, never married) (OR:6.9 [1.1–42.2]). This study provides the first national-based estimate of HPV prevalence in Tunisia. Our findings contribute to the evidence on the current burden of HPV infection, the critical role of sexual behaviour and socioeconomic status and call for increased support for the screening program in Tunisia to prevent cervical cancer. These results allow us to evaluate the cost-effectiveness of vaccine program implementation in Tunisia in future.
PMCID: PMC4907453  PMID: 27299955
17.  Young Women Engaged in Sex Work in Phnom Penh, Cambodia, Have High Incidence of HIV and Sexually Transmitted Infections, and Amphetamine-Type Stimulant Use: New Challenges to HIV Prevention and Risk 
Sexually transmitted diseases  2011;38(1):33-39.
To estimate prevalence and incidence of HIV and sexually transmitted infections (STI) and associated risk factors among young women working as sex workers (SWs) in Phnom Penh, Cambodia.
A prospective study of young (<29 years) women working as SWs in brothels, entertainment establishments, and freelance. Sociodemographics, sexual risk, and use of amphetamine-type stimulants (ATS) (“yama” and “crystal”) were assessed by self-report. HIV and STI (Chlamydia trachomatis and Neisseria gonorrhoeae) testing were conducted on blood and urine specimens, respectively.
Baseline prevalences of HIV, C. trachomatis, and N. gonorrhoeae were 23%, 11.5%, and 7.8%, respectively. HIV incidence was 3.6 per 100 person-years (95% confidence interval [CI], 1.2%– 11.1%); STI incidence was 21.2 per 100 person-years (95% CI, 12.6%– 35.8%). At baseline, 26.5% reported recent ATS use. HIV infection was associated with freelance SW (adjusted odds ratio, 5.85; 95% CI, 1.59–21.58) and younger age of first sex (≤15 years; adjusted odds ratio, 3.06; 95% CI, 1.01–8.46). Incident STI was associated with duration (per year) of SW (adjusted hazard ratio, 1.1; 95% CI, 1.1–1.2) and recent yama use (adjusted hazard ratio, 3.9; 95% CI, 1.5–10.3).
HIV and STI infection rates were high among SWs working in various settings; freelancers had highest risk. ATS use was associated with incident STI. Venue of sex work and drug prevention should be considered in prevention programs.
PMCID: PMC3729941  PMID: 21085056
18.  Human papillomavirus (HPV) types 16, 18, 31, 45 DNA loads and HPV-16 integration in persistent and transient infections in young women 
BMC Infectious Diseases  2010;10:326.
HPV burden is a predictor for high-grade cervical intraepithelial neoplasia and cancer. The natural history of HPV load in young women being recently exposed to HPV is described in this paper.
A total of 636 female university students were followed for 2 years. Cervical specimens with HPV-16, -18, -31, or -45 DNA by consensus PCR were further evaluated with type-specific and β-globin real-time PCR assays. Proportional hazards regression was used to estimate hazard ratios (HR) of infection clearance. Generalized estimating equations assessed whether HPV loads was predictive of HPV infection at the subsequent visit.
HPV loads were consistently higher among women <25 years old, and those who had multiple sex partners, multiple HPV type infections and smokers. HPV-16 integration was encountered only in one sample. Infection clearance was faster among women at lower tertiles of HPV-16 (HR = 2.8, 95%CI: 1.0-8.1), HPV-18 (HR = 3.5, 95%CI: 1.1-11.2) or combined (HR = 2.4, 95%CI: 1.8-6.2) DNA loads. The relationship between HPV-16 and HPV-18 DNA loads and infection clearance followed a clear dose-response pattern, after adjusting for age and number of sexual partners. GEE Odds Ratios for HPV persistence of the middle and upper tertiles relative to the lower tertile were 2.7 and 3.0 for HPV-16 and 3.8 and 39.1 for HPV-18, respectively. There was no association between HPV-31 or -45 DNA loads and persistence.
The association between HPV load and persistence is not uniform across high-risk genital genotypes. HPV-16 integration was only rarely demonstrated in young women.
PMCID: PMC2993709  PMID: 21070660
19.  Baseline prevalence and type distribution of human papillomavirus in healthy Chinese women aged 18–25 years enrolled in a clinical trial 
Baseline human papillomavirus (HPV) prevalence and type distribution were evaluated in young Chinese women enrolled in a clinical trial of an HPV vaccine ( registration NCT00779766). Cervical specimens and blood samples were collected at baseline from women aged 18–25 years (n = 6,051) from four sites across Jiangsu province. Cervical specimens were tested for HPV DNA by SPF10 PCR-DEIA-LiPA25 version 1, and HPV-16/18 type-specific polymerase chain reaction. Anti-HPV-16 and anti-HPV-18 antibody titres were quantified by enzyme-linked immunosorbent assay. At baseline, 15.3% of women were DNA positive for any of 14 HPV high-risk (hr) types (HPV-16/18/31/33/35/39/45/51/52/56/58/59/66/68). The most commonly detected hrHPV types in cervical specimens were HPV-52 (4.0%) and HPV-16 (3.7%). High-risk HPV DNA-positivity increased with severity of cytological abnormalities: 39.3% in atypical squamous cells of undetermined significance, 85.0% in low-grade squamous intraepithelial lesions and 97.8% in high-grade squamous intraepithelial lesions (HSIL). The hrHPV types most frequently detected in HSIL were HPV-16 (63.0%), HPV-18 (17.4%), HPV-52 (17.4%), HPV-58 (15.2%) and HPV-33 (15.2%). The hrHPV types most frequently detected in cervical intraepithelial neoplasia 2+ were HPV-16 (66.1%), HPV-33 (16.1%), HPV-52 (16.1%), HPV-58 (14.5%) and HPV-51 (11.3%). Multiple hrHPV infections were reported for 24.4% of hrHPV DNA positive women. Regardless of baseline HPV DNA status, 30.5% and 16.0% of subjects were initially seropositive for anti-HPV-16 and anti-HPV-18, respectively. In conclusion, the high baseline seropositivity rate and intermediate prevalence of cervical hrHPV types in Chinese women aged 18–25 years underlines the importance of early HPV vaccination in this population.
What's new?
In China, cervical cancer is the second most frequent cancer among women aged 15–44 years. The authors collected baseline data on prevalence and type distribution of human papillomavirus (HPV) from more than 6,000 healthy Chinese women aged 18–25 years participating in a large vaccine efficacy trial. Regardless of cytology, 15.3% of women were positive for high-risk HPV types, with HPV-52 (4.0%), HPV-16 (3.7%), HPV-51 (1.7%) and HPV-58 (1.5%) being the most frequently detected. This high baseline prevalence of high-risk HPV types underscores the importance of early vaccination among Chinese women.
PMCID: PMC4277334  PMID: 24740547
human papillomavirus; China; women; prevalence; type distribution
20.  Distribution of Human Papillomavirus Genotypes among HIV-Positive and HIV-Negative Women in Cape Town, South Africa 
Objective: HIV-positive women are known to be at high-risk of human papillomavirus (HPV) infection and its associated cervical pathology. Here, we describe the prevalence and distribution of HPV genotypes among HIV-positive and -negative women in South Africa, with and without cervical intraepithelial neoplasia (CIN).
Methods: We report data on 1,371 HIV-positive women and 8,050 HIV-negative women, aged 17–65 years, recruited into three sequential studies in Cape Town, South Africa, conducted among women who had no history of cervical cancer screening recruited from the general population. All women were tested for HIV. Cervical samples were tested for high-risk HPV DNA (Hybrid Capture 2) with positive samples tested to determine the specific genotype (Line Blot). CIN status was determined based on colposcopy and biopsy.
Results: The HPV prevalence was higher among HIV-positive women (52.4%) than among HIV-negative women (20.8%) overall and in all age groups. Younger women, aged 17–19 years, had the highest HPV prevalence regardless of HIV status. HIV-positive women were more likely to have CIN 2 or 3 than HIV-negative women. HPV 16, 35, and 58 were the most common high-risk HPV types with no major differences in the type distribution by HIV status. HPV 18 was more common in older HIV-positive women (40–65 years) with no or low grade disease, but less common in younger women (17–29 years) with CIN 2 or 3 compared to HIV-negative counterparts (p < 0.03). Infections with multiple high-risk HPV types were more common in HIV-positive than HIV-negative women, controlling for age and cervical disease status.
Conclusion: HIV-positive women were more likely to have high-risk HPV than HIV-negative women; but, among those with HPV, the distribution of HPV types was similar by HIV status. Screening strategies incorporating HPV genotyping and vaccination should be effective in preventing cervical cancer in both HIV-positive and -negative women living in sub-Saharan Africa.
PMCID: PMC3953716  PMID: 24672770
HIV-infections; HPV; genotype; HPV vaccine; cervical cancer screening
21.  An epidemiological study assessing the prevalence of human papillomavirus types in women in the Kingdom of Bahrain 
BMC Cancer  2014;14:905.
Persistent infection with high-risk (HR) human papillomavirus (HPV) causes cervical cancer, the fourth most frequent cancer in the Kingdom of Bahrain, with an annual incidence of four per 100,000 women. The aim of this study was to assess the prevalence and type distribution of HPV in Bahraini and non-Bahraini women attending routine screening. HPV prevalence was assessed by risk factors and age distribution. Health-related behaviors and HPV awareness were also studied.
This observational study was conducted between October 2010 and November 2011 in the Kingdom of Bahrain (NCT01205412). Women aged either ≥20 years attending out-patient health services for routine cervical screening or ≥16 years attending post-natal check-ups were enrolled. Cervical samples were collected and tested for HPV-DNA by polymerase chain reaction and typed using the SPF10 DEIA/LiPA25 system. All women completed two questionnaires on health-related behavior (education level, age at first marriage, number of marital partners, parity and smoking status) and HPV infection awareness.
HPV DNA was detected in 56 of the 571 women included in the final analysis (9.8%); 28 (4.9%), 15 (2.6%) and 13 (2.3%) women were infected with single, multiple and unidentifiable HPV types, respectively. The most prevalent HPV types among the HPV positive women were HR-HPV-52 in eight (1.4%), HR-HPV-16, -31 and -51 in six women each (1.1%); low-risk (LR)-HPV-6 in four (0.7%); and LR-HPV-70, -74 in three women each (0.5%). Co-infection with other HR-HPV types was observed in 50% HPV-16-positive women (with HPV-31, -45 and -56) and in both HPV-18-positive women (with HPV-52). None of the health-related risk factors studied were associated with any HR-HPV infection. More than half of women (68.7%) had never heard about HPV, but most women (91.3%) in our study were interested in HPV-vaccination.
HPV prevalence in Bahraini women was 9.8%. The most frequently observed HPV types were HR-HPV-52, -16, -31 and -51 and LR-HPV-6, -70 and -74. These are useful baseline data for health authorities to determine the potential impact of preventive measures including the use of prophylactic vaccines to reduce the burden of cervical cancer.
PMCID: PMC4265506  PMID: 25466757
Epidemiology; Human papillomavirus; Kingdom of Bahrain; Prevalence; Type distribution
22.  Epidemiological patterns of cervical human papillomavirus infection among women presenting for cervical cancer screening in North-Eastern Nigeria 
Sub-Saharan countries including Nigeria have the highest burden of Human Papillomavirus (HPV) infection in the world. Most studies on HPV surveillance in Nigeria were done in the southern part of the country. Geographical and socio-cultural diversity of Nigeria makes these data unlikely to be universally representative for the entire country. Northern Nigeria especially the North-East carries a higher prevalence of cervical cancer and many of its risk factors. The region may be harbouring a higher prevalence of HPV infection with a possibility of different genotypic distribution. This study was carried out to determine the burden and confirm the predominant HPV genotypes among women presenting for cervical cancer screening at the Federal Teaching Hospital Gombe (FTHG), North-eastern, Nigeria.
The study was an observational hospital based cross sectional study among women who presented for cervical cancer screening in FTHG. A total of 209 consenting women were tested for cervical HPV infection using PCR. DNA sequencing was carried out on positive samples to determine the prevalent HPV genotypes.
The prevalence of cervical HPV infection among the participants with mean age of 39.6 ± 10.4 years was 48.1 %. The five most predominant genotypes were 18, 16, 33, 31 and 35, with prevalence of 44.7 %, 13.2 %, 7.9 %, 5.3 % and 5.3 % respectively. Other genotypes observed were 38, 45, 56, 58, 82 and KC5. Multiple HPV infections were detected among 7.9 % of participants. Risk factors such as level of education (X2 = 15.897; p = 0.007), age at sexual debut (X2 = 6.916; p = 0.009), parity (X2 = 23.767; p = 0.000), number of life time sexual partners (X2 = 7.805; p = 0.005), age at first pregnancy (X2 = 10.554; p = 0.005) and history of other malignancies (X2 = 7.325; p = 0.007) were found to have a statistically significant association with HPV infection.
This study identified a high burden of HPV infection in Northern Nigeria while also confirming HPV 18 and 16 as the most predominant genotypes. It further justifies the potential benefit of the currently available HPV vaccines in the area. A larger and community based study is however recommended for better representation of the area.
Electronic supplementary material
The online version of this article (doi:10.1186/s13027-015-0035-8) contains supplementary material, which is available to authorized users.
PMCID: PMC4592568  PMID: 26435733
Human Papillomavirus; Genotypes; Cervix; Women; Nigeria
23.  Sexual Behaviour and HPV Infections in 18 to 29 Year Old Women in the Pre-Vaccine Era in the Netherlands 
PLoS ONE  2008;3(11):e3743.
Infection with Human Papillomavirus (HPV) is a necessary event in the multi-step process of cervical carcinogenesis. Little is known about the natural history of HPV infection among unscreened young adults. As prophylactic vaccines are being developed to prevent specifically HPV 16 and 18 infections, shifts in prevalence in the post vaccine era may be expected. This study provides a unique opportunity to gather baseline data before changes by nationwide vaccination occur.
Methods and Principal Findings
This cross-sectional study is part of a large prospective epidemiologic study performed among 2065 unscreened women aged 18 to 29 years. Women returned a self-collected cervico-vaginal specimen and filled out a questionnaire. All HPV DNA-positive samples (by SPF10 DEIA) were genotyped using the INNO-LiPA HPV genotyping assay. HPV point prevalence in this sample was 19%. Low and high risk HPV prevalence was 9.1% and 11.8%, respectively. A single HPV-type was detected in 14.9% of all women, while multiple types were found in 4.1%. HPV-types 16 (2.8%) and 18 (1.4%) were found concomitantly in only 3 women (0.1%). There was an increase in HPV prevalence till 22 years. Multivariate analysis showed that number of lifetime sexual partners was the most powerful predictor of HPV positivity, followed by type of relationship, frequency of sexual contact, age, and number of sexual partners over the past 6 months.
Conclusions and Significance
This study shows that factors independently associated with HPV prevalence are mainly related to sexual behaviour. Combination of these results with the relative low prevalence of HPV 16 and/or 18 may be promising for expanding the future target group for catch up vaccination. Furthermore, these results provide a basis for research on possible future shifts in HPV genotype prevalence, and enable a better estimate of the effect of HPV 16-18 vaccination on cervical cancer incidence.
PMCID: PMC2581437  PMID: 19011683
24.  The diversity of human papillomavirus infection among human immunodeficiency virus-infected women in Yunnan, China 
Virology Journal  2014;11:202.
Yunnan has one of the oldest and the most severe human immunodeficiency virus (HIV) epidemics in China. We conducted an observational study to evaluate the human papillomavirus (HPV) genotype distribution in relation to cervical neoplastic disease risk among HIV-infected women in Yunnan.
We screened 301 HIV-infected non-pregnant women in Mangshi prefecture in Yunnan province. All consenting participants underwent simultaneous and independent assessment by cervical cytology, colposcopy-histopathology, and HPV genotyping. Unadjusted and multivariable-adjusted multinomial logistic regression analysis was conducted to evaluate factors associated with single or multiple carcinogenic HPV genotypes.
HPV genotypes were present in 43.5% (131/301) overall, and carcinogenic HPV genotypes were present in 37.5% (113/301) women. Among women with carcinogenic HPV genotypes, 80 (70.8% of 113) had a single carcinogenic HPV type, while 33 (29.2%) women had multiple (2 or more) carcinogenic HPV types. Overall, the most common carcinogenic HPV types were HPV52 (7.3%), HPV58 (6.6%), HPV18 (6.3%), HPV16 (6.0%), and HPV33 (5.3%). In women with cervical precancerous lesions (i.e., high-grade squamous intraepithelial lesions [HSIL] on cytology or cervical intraepithelial neoplasia grade 2 or worse [CIN2+] detected on colposcopy-histology), the most commonly detected genotypes were HPV16 (28.6%), HPV52 (25.0%), HPV58 (17.9%), HPV18 (10.7%) and HPV31 (10.7%). Increasing age was an independent risk factor associated with presence of single carcinogenic HPV types (adjusted odds ratio: 1.04, 95%CI: 1.01-1.07, p = 0.012) but not with the presence of multiple carcinogenic types in the multivariable-adjusted models.
As HIV-infected women continue to live longer on antiretroviral therapy in China, it will be increasingly important to screen for, and prevent, HPV-associated cervical cancer in this population, especially given the wide diversity and multiplicity of HPV genotypes.
PMCID: PMC4279793  PMID: 25481842
HPV; Genotypes; HIV; Cervix; China
25.  The distribution of sexually-transmitted Human Papillomaviruses in HIV positive and negative patients in Zambia, Africa 
Human Papillomaviruses (HPV) are double-stranded DNA viruses, considered to be the primary etiological agents in cervical intraepithelial neoplasias and cancers. Approximately 15–20 of the 40 mucosal HPVs confer a high-risk of progression of lesions to invasive cancer. In this study, we investigated the prevalence of sexually transmitted HPVs in Human Immunodeficiency Virus (HIV) positive and negative patients in Zambia, Africa. The rate of high-risk HPV genotypes worldwide varies within each country. Thus, we sought to investigate the rates of HPV infection in sub-Saharan Africa and the potential role of HIV in affecting the HPV genotype distribution.
This retrospective cross-sectional study reports findings on the association and effects of HIV on HPV infections in an existing cohort of patients at University Teaching Hospital (UTH) Lusaka, Zambia. The objective of this study was to assess HPV prevalence, genotype distribution and to identify co-factors that influence HPV infection. Polymerase chain reaction (PCR) with two standard consensus primer sets (CpI/II and GP5+/6+) was used to test for the presence of HPV DNA. Primers specific for β-actin were used to monitor DNA quality. Vaginal lavage samples, collected between 1998-1999 from a total of 70 women, were part of a larger cohort that was also analyzed for HIV and human herpesvirus infection. Seventy of the samples yielded usable DNA. HIV status was determined by two rapid assays, Capillus and Determine. The incidence of HIV and HPV infections and HPV genotype distributions were calculated and statistical significance was determined by Chi-Squared test.
We determined that most common HPV genotypes detected among these Zambian patients were types 16 and 18 (21.6% each), which is approximately three-fold greater than the rates for HPV16, and ten-fold greater than the rates for HPV18 in the United States. The worldwide prevalence of HPV16 is approximately 14% and HPV18 is 5%. The overall ratio of high-risk (HR) to low-risk (LR) HPVs in the patient cohort was 69% and 31% respectively; essentially identical to that for the HR and LR distributions worldwide. However, we discovered that HIV positive patients were two-times as likely to have an HR HPV as HIV negative individuals, while the distribution of LR HPVs was unaffected by HIV status. Interestingly, we observed a nine-fold increase in HPV18 infection frequency in HIV positive versus HIV negative individuals.
The rate of oncogenic HPVs (type 16 and 18) in Zambia was much higher than in the U.S., potentially providing an explanation for the high-rates of cervical cancer in Zambia. Surprisingly, we discovered a strong association between positive HIV status and the prevalence of HR HPVs, and specifically HPV18.
PMCID: PMC1949816  PMID: 17634108

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