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1.  CHARACTERISTICS OF MULTIPLE AND CONCURRENT PARTNERSHIPS AMONG WOMEN AT HIGH RISK FOR HIV INFECTION 
Objectives
We examined parameters of sexual partnerships, including respondents’ participation in concurrency, belief that their partner had concurrent partnerships (partners’ concurrency), and partnership intervals, among the 2,099 women in HIV Prevention Trials Network 064, a study of women at high risk for HIV infection, in ten US communities.
Methods
We analyzed baseline survey responses about partnership dates to determine prevalence of participants’ and partners’ concurrency, intervals between partnerships, knowledge of whether recent partner(s) had undergone HIV testing, and intercourse frequency during the preceding 6 months.
Results
Prevalence of participants’ and partners’ concurrency was 40% and 36% respectively; 24% of respondents had both concurrent partnerships and non-monogamous partners. Among women with >1 partner and no concurrent partnerships themselves, the median gap between partners was one month. Multiple episodes of unprotected vaginal intercourse with >2 of their most recent partners was reported by 60% of women who had both concurrent partnerships and non-monogamous partners, 50% with only concurrent partners and no partners’ concurrency, and 33% with only partners’ concurrency versus 14% of women with neither type of concurrency (p<.0001). Women who had any involvement with concurrency were also more likely than women with no concurrency involvement to report lack of awareness of whether recent partners had undergone HIV testing (participants’ concurrency 41%, partners’ concurrency 40%, both participants’ and partners’ concurrency 48%, neither 17%; p<.0001).
Conclusions
These network patterns and short gaps between partnerships may create substantial opportunities for HIV transmission in this sample of women at high risk for HIV infection.
doi:10.1097/QAI.0b013e3182a9c22a
PMCID: PMC4172374  PMID: 24056163
2.  Summary measures of adherence using pill counts in two HIV prevention trials: the need for standardisation in reporting 
AIDS and behavior  2013;17(9):10.1007/s10461-013-0542-9.
For trials of user-dependent HIV prevention products, accurate adherence measurements are essential to interpret and compare results across trials. We used pill count data from two recent HIV prevention trials of herpes simplex virus type 2 (HSV-2) suppression, to show that estimates of adherence vary substantially depending on assumptions that are made in analysing pill count data. We associate calculated adherence with biological markers of anti-HSV-2 activity. In both trials, calculated adherence varied considerably, depending on the summary measure used, and the handling of intervals with apparent ‘over-adherence’ (fewer pills returned than expected), and unreturned pills. Intervals of apparent over-adherence were associated with reduced antiviral effects on biological markers of herpes reactivation, indicating these are likely to represent periods of non-adherence. Our results demonstrate the clear need for standardisation in reporting of adherence data that are based on pill counts.
doi:10.1007/s10461-013-0542-9
PMCID: PMC3812335  PMID: 23801018
Adherence; HIV prevention; pill counts
3.  Daily Acyclovir to Decrease Herpes Simplex Virus Type 2 (HSV-2) Transmission from HSV-2/HIV-1 Coinfected Persons: A Randomized Controlled Trial 
The Journal of Infectious Diseases  2013;208(9):1366-1374.
Background. Daily suppressive therapy with valacyclovir reduces risk of sexual transmission of herpes simplex virus type 2 (HSV-2) in HSV-2–serodiscordant heterosexual couples by 48%. Whether suppressive therapy reduces HSV-2 transmission from persons coinfected with HSV-2 and human immunodeficiency virus type 1 (HIV-1) is unknown.
Methods. Within a randomized trial of daily acyclovir 400 mg twice daily in African HIV-1 serodiscordant couples, in which the HIV-1–infected partner was HSV-2 seropositive, we identified partnerships in which HIV-1–susceptible partners were HSV-2 seronegative to estimate the effect of acyclovir on risk of HSV-2 transmission.
Results. We randomly assigned 911 HSV-2/HIV-1–serodiscordant couples to daily receipt of acyclovir or placebo. We observed 68 HSV-2 seroconversions, 40 and 28 in acyclovir and placebo groups, respectively (HSV-2 incidence, 5.1 cases per 100 person-years; hazard ratio [HR], 1.35 [95% confidence interval, .83–2.20]; P = .22). Among HSV-2–susceptible women, vaginal drying practices (adjusted HR, 44.35; P = .004) and unprotected sex (adjusted HR, 9.91; P = .002) were significant risk factors for HSV-2 acquisition; having more children was protective (adjusted HR, 0.47 per additional child; P = .012). Among HSV-2–susceptible men, only age ≤30 years was associated with increased risk of HSV-2 acquisition (P = .016).
Conclusions. Treatment of African HSV-2/HIV-1–infected persons with daily suppressive acyclovir did not decrease risk of HSV-2 transmission to susceptible partners. More-effective prevention strategies to reduce HSV-2 transmission from HIV-1–infected persons are needed.
doi:10.1093/infdis/jit333
PMCID: PMC3789565  PMID: 23901094
HSV-2; HIV-1; acyclovir; transmission; serodiscordant couples; Africa
4.  Integrated Strategies for Combination HIV Prevention: Principles and examples for men who have sex with men in the Americas and heterosexual African populations 
Combination HIV prevention is a high priority for increasing the impact of partially efficacious HIV prevention interventions for specific populations and settings. Developing the package requires critical review of local epidemiology of HIV infection regarding populations most impacted and most at risk, drivers of HIV infection, and available interventions to address these risk factors. Interventions should be considered in terms of the evidence basis for efficacy, potential synergies, feasibility of delivery at scale, which is important in order to achieve high coverage and impact, coupled with high acceptability to populations, which will impact uptake, adherence, and retention. Evaluation requires process measures of uptake, adherence, retention, and outcome measures of reduction in HIV infectiousness and acquisition. Three examples of combination prevention concepts are summarized for men who have sex with men (MSM) in the Americas, young women in sub-Saharan Africa, and HIV-1 serodiscordant couples.
doi:10.1097/QAI.0b013e3182986f3a
PMCID: PMC3708491  PMID: 23764638
Combination HIV prevention; integrated prevention; men who have sex with men; young women in Africa; HIV-1 serodiscordant couples
5.  Study Design Considerations for Evaluating Efficacy of Systemic Pre-Exposure Prophylaxis Interventions 
Background
The development of interventions for systemic Pre-Exposure Prophylaxis (PrEP) faces several significant challenges following the US Food and Drug Administration’s (FDA) approval of Emtricitabine/Tenofovir (FTC/TDF) for HIV prevention. This development is particularly complex because of inconsistency of efficacy results of FTC/TDF PrEP trials for HIV prevention.
Methods
Possible designs for a PrEP Phase 3 efficacy trial are obtained by considering scenarios for potential experimental PrEP and control regimens, including consideration of placebo and active controls, longer acting PrEP and alternate dosing schedules.
Results
Non-inferiority (NI) trials with hazard ratio NI margins ranging from 1.10 to 1.25 can be justified in the contexts of the three PrEP trials demonstrating efficacy of FTC/TDF. However these HIV endpoint trials may require extremely large numbers of participants, particularly in settings where FTC/TDF has been shown to reduce the risk of HIV acquisition. NI trials also are often difficult to interpret because they depend on prior placebo-controlled efficacy results. Superiority trials for PrEP are plausible in settings where FTC/TDF efficacy is not yet established, possibly due to low adherence (i.e. women at risk as in FemPrEP and VOICE): a new product with potential for higher adherence and potency would be a promising candidate in this setting.
Conclusions
Following FDA approval of FTC/TDF for PrEP, trials to establish efficacy of new PrEP regimens require stringent design standards, together with rigorous debate about adherence within study populations and many important ethical issues.
doi:10.1097/QAI.0b013e3182986fac
PMCID: PMC3725298  PMID: 23764624
Pre-exposure Prophylaxis; Non-inferiority; efficacy; phase 3; clinical trials; adherence
6.  HIV Acquisition Among Women From Selected Areas of the United States 
Annals of internal medicine  2013;158(1):10-18.
Background
Women account for 23% of newly diagnosed HIV infections in the United States, but there are few recent, well-characterized cohorts of U.S. women in whom behavior characteristics and HIV acquisition have been well-described.
Objective
To evaluate HIV incidence and describe behaviors among U.S. women residing in areas of high HIV prevalence.
Design
Multisite, longitudinal cohort of women who had HIV rapid testing and audio computer-assisted self-interviews at baseline and every 6 months for up to 12 months. (ClinicalTrials.gov: NCT00995176)
Setting
10 urban and periurban communities with high HIV prevalence and poverty rates, located in the northeastern and southeastern United States.
Patients
Venue-based sampling was used to recruit women aged 18 to 44 years who recently had unprotected sex and had 1 or more additional personal or partner risk factors and no self-reported previous HIV diagnosis.
Measurements
HIV prevalence and incidence, frequency of HIV risk behaviors, and health status perceptions.
Results
Among 2099 high-risk women (85.9% black and 11.7% of Hispanic ethnicity), 32 (1.5%) were diagnosed with HIV infection at enrollment. Annual HIV incidence was 0.32% (95% CI, 0.14% to 0.74%). Older age, substance use, and knowing a partner had HIV were associated with HIV prevalence. Ten women died during the study (0.61% per year).
Limitations
Longitudinal assessment of risk behaviors was limited to a maximum of 12 months. There were few incident HIV infections, precluding identification of characteristics predictive of HIV acquisition.
Conclusion
This study enrolled a cohort of women with HIV incidence substantially higher than the Centers for Disease Control and Prevention national estimate in the general population of U.S. black women. Concerted efforts to improve preventive health care strategies for HIV and overall health status are needed for similar populations.
doi:10.7326/0003-4819-158-1-201301010-00004
PMCID: PMC4033695  PMID: 23277896
7.  QUANTITATIVE HUMAN PAPILLOMAVIRUS 16 AND 18 LEVELS IN INCIDENT INFECTIONS AND CERVICAL LESION DEVELOPMENT 
Journal of medical virology  2009;81(4):713-721.
Human papillomavirus (HPV) RNA levels may be a more sensitive early indicator of predisposition to carcinogenesis than DNA levels. We evaluated whether levels of HPV-16 and HPV-18 DNA and messenger RNA (mRNA) in newly detected infections are associated with cervical lesion development. Female university students were recruited from 1990-2004. Cervical samples for HPV DNA, HPV mRNA, and Papanicolaou testing were collected tri-annually, and women were referred for colposcopically-directed biopsy when indicated. Quantitative real-time polymerase chain reaction of L1 and E7 DNA and E7 mRNA was performed on samples from women with HPV-16 and HPV-18 infections that were incidently detected by consensus PCR. Adjusting for other HPV types, increasing E7 cervical HPV-16 mRNA levels at the time of incident HPV-16 DNA detection were associated with an increased risk of cervical intraepithelial neoplasia grade 2 to 3 (HR per 1 log10 increase in mRNA=6.36,95%CI=2.00-20.23). Increasing HPV-16 mRNA levels were also associated with an increased risk of cervical squamous intraepithelial lesions; the risk was highest at the incident positive visit and decreased over time. Neither HPV-16 E7 DNA levels nor HPV-18 E7 DNA nor mRNA levels were significantly associated with cervical lesion development. Report of >1 new partner in the past 8 months (relative to no new partners) was associated with increased HPV mRNA (viral level ratio [VLR]=10.05,95%CI=1.09-92.56) and increased HPV DNA (VLR=16.80,95%CI=1.46-193.01). In newly detected HPV-16 infections, increasing levels of E7 mRNA appear to be associated with an increased risk of developing cervical pre-cancer.
doi:10.1002/jmv.21450
PMCID: PMC3984467  PMID: 19235870
HPV; viral load; mRNA; cervical pre-cancer
8.  Plasma Viral Loads During Early HIV-1 Infection Are Similar in Subtype C– and Non-Subtype C–Infected African Seroconverters 
The Journal of Infectious Diseases  2013;207(7):1166-1170.
Recent data suggest that infection with human immunodeficiency virus type 1 (HIV-1) subtype C results in prolonged high-level viremia (>5 log10 copies/mL) during early infection. We examined the relationship between HIV-1 subtype and plasma viremia among 153 African seroconverters. Mean setpoint viral loads were similar for C and non-C subtypes: 4.36 vs 4.42 log10 copies/mL (P = .61). The proportion of subtype C–infected participants with viral loads >5 log10 copies/mL was not greater than the proportion for those with non-C infection. Our data do not support the hypothesis that higher early viral load accounts for the rapid spread of HIV-1 subtype C in southern Africa.
doi:10.1093/infdis/jit015
PMCID: PMC3583276  PMID: 23315322
HIV-1; group M subtype; plasma viral load; early infection; Africa
9.  Standard Treatment Regimens for Nongonococcal Urethritis Have Similar but Declining Cure Rates: A Randomized Controlled Trial 
Cure rates for nongonococcal urethritis (NGU), were approximately 80% and there was no significant difference between azithromycin and doxycycline for clinical or microbiologic cure. Chlamydia trachomatis, Ureaplasma urealyticum biovar 2, and idiopathic NGU remained relatively sensitive to standard therapies, but Mycoplasma genitalium was not.
Background. Azithromycin or doxycycline is recommended for nongonococcal urethritis (NGU); recent evidence suggests their efficacy has declined. We compared azithromycin and doxycycline in men with NGU, hypothesizing that azithromycin was more effective than doxycycline.
Methods. From January 2007 to July 2011, English-speaking males ≥16 years, attending a sexually transmitted diseases clinic in Seattle, Washington, with NGU (visible urethral discharge or ≥5 polymorphonuclear leukocytes per high-power field [PMNs/HPF]) were eligible for this double-blind, parallel-group superiority trial. Participants received active azithromycin (1 g) + placebo doxycycline or active doxycycline (100 mg twice daily for 7 days) + placebo azithromycin. Urine was tested for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), Ureaplasma urealyticum biovar 2 (UU-2), and Trichomonas vaginalis (TV) using nucleic acid amplification tests. Clinical cure (<5 PMNs/HPF with or without urethral symptoms and absence of discharge) and microbiologic cure (negative tests for CT, MG, and/or UU-2) were determined after 3 weeks.
Results. Of 606 men, 304 were randomized to azithromycin and 302 to doxycycline; CT, MG, TV, and UU-2 were detected in 24%, 13%, 2%, and 23%, respectively. In modified intent-to-treat analyses, 172 of 216 (80%; 95% confidence interval [CI], 74%–85%) receiving azithromycin and 157 of 206 (76%; 95% CI, 70%–82%) receiving doxycycline experienced clinical cure (P = .40). In pathogen-specific analyses, clinical cure did not differ by arm, nor did microbiologic cure differ for CT (86% vs 90%, P = .56), MG (40% vs 30%, P = .41), or UU-2 (75% vs 70%, P = .50). No unexpected adverse events occurred.
Conclusions. Clinical and microbiologic cure rates for NGU were somewhat low and there was no significant difference between azithromycin and doxycycline. Mycoplasma genitalium treatment failure was extremely common.
Clinical Trials Registration. NCT00358462.
doi:10.1093/cid/cis1022
PMCID: PMC3588116  PMID: 23223595
urethritis; treatment; Mycoplasma genitalium; Chlamydia trachomatis; randomized trial
10.  An empiric risk scoring tool for identifying high-risk heterosexual HIV-1 serodiscordant couples for targeted HIV-1 prevention 
Background and objectives
Heterosexual HIV-1 serodiscordant couples are increasingly recognized as an important source of new HIV-1 infections in sub-Saharan Africa. A simple risk assessment tool could be useful for identifying couples at highest risk for HIV-1 transmission.
Methods
Using data from three prospective studies of HIV-1 serodiscordant couples from seven African countries and standard methods for development of clinical prediction rules, we derived and validated a risk scoring tool developed from multivariate modeling and composed of key predictors for HIV-1 risk that could be measured in standard research and clinical settings.
Results
The final risk score included age of the HIV-1 uninfected partner, married and/or cohabiting partnership, number of children, unprotected sex, uncircumcised male HIV-1 uninfected partner, and plasma HIV-1 RNA in the HIV-1 infected partner. The maximum risk score was 12, scores ≥5 were associated with an annual HIV-1 incidence of >3%, and couples with a score ≥6 accounted for only 28% of the population but 67% of HIV-1 transmissions. The area under the curve for predictive ability of the score was 0.74 (95% CI 0.70–0.78). Internal and external validation showed similar predictive ability of the risk score, even when plasma viral load was excluded from the risk score.
Conclusions
A discrete combination of clinical and behavioral characteristics defines highest-risk HIV-1 serodiscordant couples. Discriminating highest-risk couples for HIV-1 prevention programs and clinical trials using a validated risk score could improve research efficiency and maximize the impact of prevention strategies for reducing HIV-1 transmission.
doi:10.1097/QAI.0b013e31827e622d
PMCID: PMC3620695  PMID: 23187945
HIV-1 serodiscordant couples; HIV-1 acquisition; clinical prediction rule
11.  Determinants of Per-Coital-Act HIV-1 Infectivity Among African HIV-1–Serodiscordant Couples 
The Journal of Infectious Diseases  2012;205(3):358-365.
(See the editorial commentary by Gray and Wawer on pages 351–2.)
Background. Knowledge of factors that affect per-act infectivity of human immunodeficiency virus type 1 (HIV-1) is important for designing HIV-1 prevention interventions and for the mathematical modeling of the spread of HIV-1.
Methods. We analyzed data from a prospective study of African HIV-1–serodiscordant couples. We assessed transmissions for linkage within the study partnership, based on HIV-1 sequencing. The primary exposure measure was the HIV-1–seropositive partners’ reports of number of sex acts and condom use with their study partner.
Results. Of 3297 couples experiencing 86 linked HIV-1 transmissions, the unadjusted per-act risks of unprotected male-to-female (MTF) and female-to-male (FTM) transmission were 0.0019 (95% confidence interval [CI], .0010–.0037) and 0.0010 (95% CI, .00060–.0017), respectively. After adjusting for plasma HIV-1 RNA of the HIV-1–infected partner and herpes simplex virus type 2 serostatus and age of the HIV-1–uninfected partner, we calculated the relative risk (RR) for MTF versus FTM transmission to be 1.03 (P = .93). Each log10 increase in plasma HIV-1 RNA increased the per-act risk of transmission by 2.9-fold (95% CI, 2.2–3.8). Self-reported condom use reduced the per-act risk by 78% (RR = 0.22 [95% CI, .11–.42]).
Conclusions. Modifiable risk factors for HIV-1 transmission were plasma HIV-1 RNA level and condom use, and, in HIV-1–uninfected partners, herpes simplex virus 2 infection, genital ulcers, Trichomonas vaginalis, vaginitis or cervicitis, and male circumcision.
doi:10.1093/infdis/jir747
PMCID: PMC3256946  PMID: 22241800
12.  Estimating the Efficacy of Preexposure Prophylaxis for HIV Prevention Among Participants With a Threshold Level of Drug Concentration 
American Journal of Epidemiology  2013;177(3):256-263.
Assays for detecting levels of antiretroviral drugs in study participants are increasingly popular in preexposure prophylaxis (PrEP) trials, since they provide an objective measure of adherence. Current correlation analyses of drug concentration data are prone to bias. In this article, we formulate the causal estimand of prevention efficacy among drug compliers, those who would have had a threshold level of drug concentration had they been assigned to the drug arm of the trial. The identifiability of the causal estimand is facilitated by exploiting the exclusion restriction; that is, drug noncompliers do not acquire any prevention benefit. In addition, we develop an approach to sensitivity analysis that relaxes the exclusion restriction. Applications to published data from 2 PrEP trials, namely the Preexposure Prophylaxis Initiative (iPrEx) trial and the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 trial, suggest high efficacy estimates among drug compliers (in the iPrEx trial, odds ratio = 0.097 (95% confidence interval: 0.027, 0.352); in the CAPRISA 004 trial, odds ratio = 0.104 (95% confidence interval: 0.024, 0.447)). In summary, the proposed inferential method provides an unbiased assessment of PrEP efficacy among drug compliers, thus adding to the primary intention-to-treat analysis and correlation analyses of drug concentration data.
doi:10.1093/aje/kws324
PMCID: PMC3577049  PMID: 23302152
causal inference; compliance; exclusion restriction; potential outcome; principal stratification; two-phase sampling
13.  Use of a Multifaceted Approach to Analyze HIV Incidence in a Cohort Study of Women in the United States: HIV Prevention Trials Network 064 Study 
The Journal of Infectious Diseases  2012;207(2):223-231.
Background. Reliable methods for estimating the incidence of human immunodeficiency virus (HIV) infection are needed to monitor the epidemic, identify at-risk populations, and evaluate HIV prevention strategies. We used a multifaceted approach to estimate HIV incidence in the HIV Prevention Trials Network (HPTN) 064 study.
Methods. The HPTN 064 study enrolled 2067 HIV-seronegative women and 32 HIV-seropositive women with no prior HIV infection diagnosis. Women were followed for up to 12 months. HIV incidence estimates were based on (1) detection of acute HIV infection, (2) documentation of HIV seroconversion, and (3) detection of recent HIV infection, using a multiassay algorithm (MAA).
Results. Two women had acute HIV infection at enrollment, 4 seroconverted, and 2 were identified as recently infected at enrollment using the MAA. The annual HIV incidence estimate based on acute infection at enrollment (2.52% [95% confidence interval {CI}, .17%–9.33%], using a 14-day window period) was higher than the estimate based on seroconversion (0.24% [95% CI, .07%–.62%]; P = .027). Incidence estimates obtained using the MAA at enrollment and at the end of study were 0.25% (95% CI, .03%–.93%) and 0.13% (95% CI, .006%–.76%), respectively.
Conclusions. We detected a high frequency of acute infection at enrollment. Cross-sectional HIV incidence estimates obtained using the MAA were similar to the longitudinal estimate based on HIV seroconversion.
Clinical Trials Registration. NCT00995176.
doi:10.1093/infdis/jis658
PMCID: PMC3532822  PMID: 23129758
HIV-1; women; United States; incidence
14.  Partner Characteristics Predicting HIV-1 Set Point in Sexually Acquired HIV-1 Among African Seroconverters 
Abstract
Plasma HIV-1 RNA set point is an important predictor of HIV-1 disease progression. We hypothesized that inoculum size and HIV-1 exposure prior to HIV-1 transmission may modulate set point. We evaluated predictors of set point among 141 African HIV-1 seroconverters and their HIV-1-infected study partners. We compared characteristics of seroconverters and their HIV-1-infected partners and HIV-1 set point. Data were from a clinical trial of genital HSV-2 suppression with acyclovir to reduce HIV-1 transmission in HIV-1 serodiscordant couples with HIV-1 transmission linkage assigned through virus sequencing. Our analysis includes data from all transmissions including those with transmission linkage to the HIV-1-infected “source partner” and those that were not linked to their HIV-1-infected study partner. In multivariable analysis, higher plasma HIV-1 in source partners was associated with higher seroconverter set point (+0.44 log10 copies/ml per log10 source partner plasma HIV-1, p<0.001). In addition, bacterial vaginosis (BV) among female source partners near the time of infection was associated with higher set point in their male seroconverters (+0.49 log10, p=0.04). Source partner characteristics associated with lower set point included male circumcision (−0.63 log10, p=0.03) and assignment to acyclovir (−0.44 log10, p=0.02). The proportion of variation in set point explained by plasma HIV-1 RNA of the source partner, after controlling for other factors, was 0.06. Source partner plasma HIV-1 level is the most significant predictor of seroconverter set point, possibly reflecting characteristics of the transmitted virus. Acyclovir use, BV among women source partners, and circumcision among male source partners may alter the set point by affecting transmitted virus inoculum in the source partners' genital compartment.
doi:10.1089/aid.2012.0206
PMCID: PMC3537302  PMID: 23061422
15.  Prevalence and risk factors for oncogenic HPV infections in high-risk mid-adult women 
Sexually transmitted diseases  2012;39(11):848-856.
Background
The epidemiology of high-risk (hr) HPV infections in mid-adult women with new sex partners is undefined.
Methods
We analyzed baseline data from 518 25–65 year old female online daters. Women were mailed questionnaires and kits for self-collecting vaginal specimens for PCR-based hrHPV testing. Risk factors for infection were identified using Poisson regression models to obtain prevalence ratios (PRs).
Results
The prevalence of hrHPV infection was 35.9%. In multivariate analysis restricted to sexually active women, the likelihood of hrHPV infection was associated with abnormal Pap test history (PR=1.42, 95% CI:1.10–1.84), lifetime number of sex partners >14 (relative to 1–4; PR=2.13, 95% CI:1.13–4.02 for 15–24 partners and PR=1.91, 95% CI:1.00–3.64 for ≥25 partners), male partners with ≥1 concurrent partnership (PR=1.34, 95% CI:1.05–1.71) and male partners whom the subject met online (PR=1.39, 95% CI:1.08–1.79). Age was inversely associated with infection only in women who were sexually inactive (PR=0.67 per 5-year age difference, adjusted for Pap history and lifetime number of partners). Compared to sexually inactive women, the likelihood of infection increased with increasing risk level, (from low-risk to high-risk partners) (p<.0001 by trend test). In multivariate analysis, infection with multiple versus single hrHPV types was inversely associated with ever having been pregnant (PR=0.64, 95% CI:0.46–0.90) and recent consistent condom use (PR=0.56, 95% CI:0.32–0.97), and positively associated with genital wart history (PR=1.43, 95% CI:1.03–1.99).
Conclusions
Measures of both cumulative and recent sexual history were associated with prevalent hrHPV infection in this high-risk cohort of mid-adult women.
doi:10.1097/OLQ.0b013e3182641f1c
PMCID: PMC3476060  PMID: 23064533
HPV; human papilloma virus; mid-adult; prevalence; risk factors
16.  A unified procedure for meta-analytic evaluation of surrogate end points in randomized clinical trials 
Biostatistics (Oxford, England)  2012;13(4):609-624.
The meta-analytic approach to evaluating surrogate end points assesses the predictiveness of treatment effect on the surrogate toward treatment effect on the clinical end point based on multiple clinical trials. Definition and estimation of the correlation of treatment effects were developed in linear mixed models and later extended to binary or failure time outcomes on a case-by-case basis. In a general regression setting that covers nonnormal outcomes, we discuss in this paper several metrics that are useful in the meta-analytic evaluation of surrogacy. We propose a unified 3-step procedure to assess these metrics in settings with binary end points, time-to-event outcomes, or repeated measures. First, the joint distribution of estimated treatment effects is ascertained by an estimating equation approach; second, the restricted maximum likelihood method is used to estimate the means and the variance components of the random treatment effects; finally, confidence intervals are constructed by a parametric bootstrap procedure. The proposed method is evaluated by simulations and applications to 2 clinical trials.
doi:10.1093/biostatistics/kxs003
PMCID: PMC3616754  PMID: 22394448
Causal inference; Meta-analysis; Surrogacy
17.  Disclosure of Genital Human Papillomavirus Infection to Female Sex Partners by Young Men 
Sexually Transmitted Diseases  2012;39(8):583-587.
A survey was administered to male university students testing positive for high-risk human papillomavirus. Disclosure was more likely in men with fewer partners, in main partnerships, and in longer partnerships. Disclosure was associated with discussing the Pap test/HPV vaccine with female partners and not associated with a worsening relationship.
doi:10.1097/OLQ.0b013e318254c982
PMCID: PMC3398400  PMID: 22797688
human papillomavirus; male; disclosure; sexually transmitted infection; sexual partnerships
18.  Summary Measures of Adherence Using Pill Counts in Two HIV Prevention Trials: The Need for Standardisation in Reporting 
AIDS and Behavior  2013;17(9):3108-3119.
For trials of user-dependent HIV prevention products, accurate adherence measurements are essential to interpret and compare results across trials. We used pill count data from two recent HIV prevention trials of herpes simplex virus type 2 (HSV-2) suppression, to show that estimates of adherence vary substantially depending on assumptions that are made in analysing pill count data. We associate calculated adherence with biological markers of anti-HSV-2 activity. In both trials, calculated adherence varied considerably, depending on the summary measure used, and the handling of intervals with apparent ‘over-adherence’ (fewer pills returned than expected), and unreturned pills. Intervals of apparent over-adherence were associated with reduced antiviral effects on biological markers of herpes reactivation, indicating these are likely to represent periods of non-adherence. Our results demonstrate the clear need for standardisation in reporting of adherence data that are based on pill counts.
doi:10.1007/s10461-013-0542-9
PMCID: PMC3812335  PMID: 23801018
Adherence; HIV prevention; Pill counts
19.  Estimating duration in partnership studies: issues, methods and examples 
Background and objectives
Understanding the time course of sexual partnerships is important for understanding sexual behaviour, transmission risks for sexually transmitted infections (STI) and development of mathematical models of disease transmission.
Study design
The authors describe issues and biases relating to censoring, truncation and sampling that arise when estimating partnership duration. Recommendations for study design and analysis methods are presented and illustrated using data from a sexual-behaviour survey that enrolled individuals from an adolescent-health clinic and two STD clinics. Survey participants were queried, for each of (up to) four partnerships in the last 3 months, about the month and year of first sex, the number of days since last sex and whether partnerships were limited to single encounters. Participants were followed every 4 months for up to 1 year.
Results
After adjustment for censoring and truncation, the estimated median duration of sexual partnerships declined from 9 months (unadjusted) to 1.6 months (adjusted). Similarly, adjustment for censoring and truncation reduced the bias in relative risks for the effect of age in a Cox model. Other approaches, such as weighted estimation, also reduced bias in the estimated duration distribution.
Conclusion
Methods are available for estimating partnership duration from censored and truncated samples. Ignoring censoring, truncation and other sampling issues results in biased estimates.
doi:10.1136/sti.2009.037960
PMCID: PMC3050014  PMID: 20332366
20.  Evidence of immune memory 8.5 years following administration of a prophylactic human papillomavirus type 16 vaccine 
Journal of Clinical Virology  2011;53(3):239-243.
Background
The duration of protection conferred by prophylactic human papillomavirus (HPV) L1 virus-like particle vaccines is a critical determinant of their public health impact. A feature of vaccines that confer long-term immunity is their ability to induce immune memory.
Objectives
We evaluated antibody responses against HPV types 6, 11, 16 and 18 following administration of the quadrivalent HPV-6/11/16/18 vaccine to women who had previously received a monovalent HPV-16 vaccine.
Study design
As part of an extended follow-up study conducted between 2006 and 2009 in Seattle, Washington, we administered the quadrivalent HPV-6/11/16/18 vaccine to 52 women (19 vaccine and 33 placebo recipients) who had participated in a monovalent HPV-16 vaccine trial 8.5 years earlier. Serum samples were tested for anti-HPV antibodies using competitive Luminex immunoassay.
Results
Following administration of the first dose of the quadrivalent HPV-6/11/16/18 vaccine, the anti-HPV-16 geometric mean titer among monovalent HPV-16 vaccine recipients (GMT = 5024.0 milli-Merck units per milliliter [mMU/mL]; 95% confidence interval [CI]: 2710.1, 9313.6 mMU/mL) substantially exceeded that among the placebo recipients (GMT = 136.1; 95% CI: 78.5, 235.8 mMU/mL; p < 0.01) and their own highest anti-HPV-16 response observed during the original trial (GMT at month 7 of the original trial = 1552.7 mMU/mL; 95% CI: 1072.6, 2247.7 mMU/mL; p < 0.01).
Conclusions
The findings suggest that the administration of the three-dose regimen of the monovalent HPV-16 vaccine had produced memory lymphocytes, characterized by a heightened immune response following administration of the quadrivalent HPV-6/11/16/18 vaccine that effectively served as an antigen challenge.
doi:10.1016/j.jcv.2011.12.009
PMCID: PMC3279625  PMID: 22209292
Human papillomavirus type 16; Vaccines; Immune memory
21.  Understanding the Potential Impact of a Combination HIV Prevention Intervention in a Hyper-Endemic Community 
PLoS ONE  2013;8(1):e54575.
Objectives
Despite demonstrating only partial efficacy in preventing new infections, available HIV prevention interventions could offer a powerful strategy when combined. In anticipation of combination HIV prevention programs and research studies we estimated the population-level impact of combining effective scalable interventions at high population coverage, determined the factors that influence this impact, and estimated the synergy between the components.
Methods
We used a mathematical model to investigate the effect on HIV incidence of a combination HIV prevention intervention comprised of high coverage of HIV testing and counselling, risk reduction following HIV diagnosis, male circumcision for HIV-uninfected men, and antiretroviral therapy (ART) for HIV-infected persons. The model was calibrated to data for KwaZulu-Natal, South Africa, where adult HIV prevalence is approximately 23%.
Results
Compared to current levels of HIV testing, circumcision, and ART, the combined intervention with ART initiation according to current guidelines could reduce HIV incidence by 47%, from 2.3 new infections per 100 person-years (pyar) to 1.2 per 100 pyar within 4 years and by almost 60%, to 1 per 100 pyar, after 25 years. Short-term impact is driven primarily by uptake of testing and reductions in risk behaviour following testing while long-term effects are driven by periodic HIV testing and retention in ART programs. If the combination prevention program incorporated HIV treatment upon diagnosis, incidence could be reduced by 63% after 4 years and by 76% (to about 0.5 per 100 pyar) after 15 years. The full impact of the combination interventions accrues over 10–15 years. Synergy is demonstrated between the intervention components.
Conclusion
High coverage combination of evidence-based strategies could generate substantial reductions in population HIV incidence in an African generalized HIV epidemic setting. The full impact could be underestimated by the short assessment duration of typical evaluations.
doi:10.1371/journal.pone.0054575
PMCID: PMC3553021  PMID: 23372738
22.  Clinical and Virologic Response to Episodic Acyclovir for Genital Ulcers among HIV-1 Seronegative, HSV-2 Seropositive African Women: A Randomized, Placebo-Controlled Trial 
Sexually transmitted diseases  2012;39(1):21-24.
In a randomized trial among African women with recurrent genital herpes, episodic acyclovir therapy resulted in modestly greater likelihood of lesion healing (HR=1.48, p=0.098; mean 5.1 vs. 6.0 days) and cessation of HSV shedding (HR=1.88, p=0.008; mean 3.0 vs. 5.0 days) compared with placebo, similar to results from high-income countries. (ClinicalTrials.gov registration NCT00808405).
doi:10.1097/OLQ.0b013e31823b50c6
PMCID: PMC3244838  PMID: 22183840
herpes simplex virus; acyclovir; HSV shedding; women; Africa; genital herpes
23.  Analysis of Genetic Linkage of HIV From Couples Enrolled in the HIV Prevention Trials Network 052 Trial 
The Journal of Infectious Diseases  2011;204(12):1918-1926.
Background. The HIV Prevention Trials Network (HPTN) 052 trial demonstrated that early initiation of antiretroviral therapy (ART) reduces human immunodeficiency virus (HIV) transmission from HIV-infected adults (index participants) to their HIV-uninfected sexual partners. We analyzed HIV from 38 index-partner pairs and 80 unrelated index participants (controls) to assess the linkage of seroconversion events.
Methods. Linkage was assessed using phylogenetic analysis of HIV pol sequences and Bayesian analysis of genetic distances between pol sequences from index-partner pairs and controls. Selected samples were also analyzed using next-generation sequencing (env region).
Results. In 29 of the 38 (76.3%) cases analyzed, the index was the likely source of the partner’s HIV infection (linked). In 7 cases (18.4%), the partner was most likely infected from a source other than the index participant (unlinked). In 2 cases (5.3%), linkage status could not be definitively established.
Conclusions. Nearly one-fifth of the seroconversion events in HPTN 052 were unlinked. The association of early ART and reduced HIV transmission was stronger when the analysis included only linked events. This underscores the importance of assessing the genetic linkage of HIV seroconversion events in HIV prevention studies involving serodiscordant couples.
doi:10.1093/infdis/jir651
PMCID: PMC3209811  PMID: 21990420
24.  Using Plasma Viral Load to Guide Antiretroviral Therapy Initiation to Prevent HIV-1 Transmission 
PLoS ONE  2012;7(11):e51192.
Background
Current WHO guidelines recommend antiretroviral therapy (ART) initiation at CD4 counts ≤350 cells/µL. Increasing this threshold has been proposed, with a primary goal of reducing HIV-1 infectiousness. Because the quantity of HIV-1 in plasma is the primary predictor of HIV-1 transmission, consideration of plasma viral load in ART initiation guidelines is warranted.
Methods
Using per-sex-act infectivity estimates and cross-sectional sexual behavior data from 2,484 HIV-1 infected persons with CD4 counts >350 enrolled in a study of African heterosexual HIV-1 serodiscordant couples, we calculated the number of transmissions expected and the number potentially averted under selected scenarios for ART initiation: i) CD4 count <500 cells/µL, ii) viral load ≥10,000 or ≥50,000 copies/mL and iii) universal treatment. For each scenario, we estimated the proportion of expected infections that could be averted, the proportion of infected persons initiating treatment, and the ratio of these proportions.
Results
Initiating treatment at viral load ≥50,000 copies/mL would require treating 19.8% of infected persons with CD4 counts >350 while averting 40.5% of expected transmissions (ratio 2.0); treating at viral load ≥10,0000 copies/mL had a ratio of 1.5. In contrast, initiation at CD4 count <500 would require treating 41.8%, while averting 48.4% (ratio 1.1).
Conclusion
Inclusion of viral load in ART initiation guidelines could permit targeting ART resources to HIV-1 infected persons who have a higher risk of transmitting HIV-1. Further work is needed to estimate costs and feasibility.
doi:10.1371/journal.pone.0051192
PMCID: PMC3511400  PMID: 23250272
25.  Circumcision and acquisition of HPV infection in young men 
Sexually transmitted diseases  2011;38(11):1074-1081.
Background
The role of circumcision in male HPV acquisition is not clear.
Methods
Male university students (18–20 years of age) were recruited from 2003–2009 and followed tri-annually. Shaft/scrotum, glans, and urine samples were tested for 37 alpha HPV genotypes. Cox proportional hazards methods were used to evaluate the association between circumcision and HPV acquisition. Logistic regression was used to assess whether number of genital sites infected at incident HPV detection or site of incident detection varied by circumcision status.
Results
In 477 men, rates of acquiring clinically-relevant HPV types (high-risk types plus types 6 and 11) did not differ significantly by circumcision status (hazard ratio [HR] for uncircumcised relative to circumcised subjects: 0.9[95%CI:0.7–1.2]). However, compared to circumcised men, uncircumcised men were 10.1 (95%CI:2.9–35.6) times more likely to have the same HPV type detected in all 3 genital specimens than in a single genital specimen and were 2.7 (95%CI:1.6–4.5) times more likely to have an HPV-positive urine or glans specimen at first detection.
Conclusions
While the likelihood of HPV acquisition did not differ by circumcision status, uncircumcised men were more likely than circumcised men to have infections detected at multiple genital sites, which may have implications for HPV transmission.
doi:10.1097/OLQ.0b013e31822e60cb
PMCID: PMC3210112  PMID: 21992987
HPV; human papilloma virus; circumcision; epidemiology; risk factors

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