Efficacy dilution in randomized placebo-controlled vaginal microbicide trials

Mâsse, Benoı̂t; Boily, Marie-Claude; Dimitrov, Dobromir; Desai, Kamal

doi:10.1186/1742-7622-6-5

Cited by 61 publications

(51 citation statements)

References 19 publications

(28 reference statements)

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“…Indeed, in the phase 3 Carraguard trial, where women were interviewed faceto-face, between 1 and 2% of women reported anal sex [12], similar to the percentage reporting anal sex among the FTFI group here, but considerably less than the 5-8% reported by ACASI participants. If unprotected anal sex is common and a large proportion of HIV infections are due to receptive anal intercourse, the ability to detect a protective effect in a vaginal product will be undermined [31].…”

Section: Resultsmentioning

confidence: 99%

Assessing the Reporting of Adherence and Sexual Activity in a Simulated Microbicide Trial in South Africa: An Interview Mode Experiment Using a Placebo Gel

et al. 2010

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Misreporting of adherence undermines detection of an association between product use and HIV infection in microbicide trials. This study investigates whether, in a placebo trial, audio computer-assisted self-interviewing (ACASI) produces more accurate reporting of adherence and sexual behavior than a face-to-face interview (FTFI). At three South African clinics, 849 women were enrolled and instructed to use applicators filled with placebo gel; participants were randomly assigned to FTFI or ACASI. Behavioral reports were validated through two biomarkers that detect product usage and unprotected sex. For most behaviors, ACASI generated significantly higher reporting, although differences by interview mode appeared to diminish over time. ACASI participants were more likely to report having had sex without gel, but reported and tested applicators did not indicate greater honesty about gel insertion with ACASI. While comparisons of reported unprotected sex with the validated biomarker revealed more agreement with ACASI than with FTFI, differences were small.

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Section: Resultsmentioning

confidence: 99%

Assessing the Reporting of Adherence and Sexual Activity in a Simulated Microbicide Trial in South Africa: An Interview Mode Experiment Using a Placebo Gel

et al. 2010

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“…During clinical trials of intravaginal products, even modest rates of anal sex in a population may allow for HIV transmission and, if not accounted for, may mask the true effectiveness of a product. 11,12 Furthermore, anal sex was associated with lower reported rates of condom use, highlighting the importance of this sexual behavior even among heterosexual women. Current plans for clinical development of rectal microbicides include trials in women.…”

Section: Discussionmentioning

confidence: 99%

“…[7][8][9] And high rates of unprotected anal intercourse may diminish the measured effectiveness of intravaginal products in preventing HIV infection. [10][11][12] In preparation for future studies of intravaginal HIV prevention methods, we assessed HIV risk behavior, HIV incidence, prevalence of STIs and vaginitis, vaginal practices, and retention in a newly described cohort of HIV-uninfected female sex workers (FSW) in urban Kenya. HIV prevalence from 30% to 67% has been documented in Kenyan FSW cohorts, 13,14 however recent attempts to identify HIVuninfected FSW cohorts with incidence sufficient for HIV prevention trials have been difficult.…”

mentioning

confidence: 99%

Anal Sex, Vaginal Practices, and HIV Incidence in Female Sex Workers in Urban Kenya: Implications for the Development of Intravaginal HIV Prevention Methods

Priddy

Wakasiaka

Hoang

et al. 2011

AIDS Research and Human Retroviruses

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Multiple intravaginal HIV prevention methods, including microbicide gels, barriers, and intravaginal rings, are in clinical development in Africa. Development of intravaginal HIV prevention products requires an understanding of sexual behavior, sexually transmitted infection (STI), and vaginitis prevalences, and sexual and vaginal practices in potential target populations. We assessed these factors in a cohort of Kenyan female sex workers (FSW). Women who reported exchanging sex for money/gifts at least three times in the past month and who were HIV uninfected were enrolled and followed for 6 months. STI prevalence and HIV incidence were analyzed by multivariate logistic regression analysis, controlling for demographic and behavioral factors. Thirtyseven percent (74/200) reported having had anal sex. Frequency of anal sex was higher with regular and casual partners than with primary partners. Women were less likely to use condoms for anal sex than for vaginal sex with regular or casual partners. Vaginal washing was universal (100%). HIV incidence was 5.6 per 100 personyears (95% CI 1.62, 11.67). HIV incidence was not associated with any demographic or risk behavior. The relatively high rate of anal sex and universal vaginal washing may complicate both safety and efficacy evaluation of intravaginal products and should be taken into account in trial design. This FSW population had significant HIV incidence and needs continued HIV prevention interventions.

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“…However, the role of UAI as a determinant of heterosexual HIV epidemics has not been sufficiently examined [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Prevalence and Frequency of Heterosexual Anal Intercourse Among Young People: A Systematic Review and Meta-analysis

et al. 2015

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Abstract:We aim to assess if heterosexual anal intercourse (AI) is commonly practiced and how frequently it is practiced by young people.We searched PubMed for articles published 1975 to July 2014 reporting data on the proportion of young people (mean age <25) practicing heterosexual AI (AI prevalence) and on number of AI acts (AI frequency). Stratified random-effects meta-analysis and meta-regression were used to produce summary estimates and assess the influence of participant and study characteristics on AI prevalence.Eighty-three and thirteen of the 136 included articles reported data on lifetime AI prevalence and monthly AI frequency, respectively. Estimates were heterogenous. Overall summary estimates of lifetime AI prevalence were 22% (95% confidence interval (CI) 20-24%) among sexually active young people, with no statistically significant differences by gender, continent or age. Prevalence increased significantly with confidentiality of interview method and, among males and in Europe, by survey year. Prevalence did not significantly differ by recall period. An estimated 3-24% of all reported sex acts were AI.Reported heterosexual AI is common but variable among young people worldwide. To fully understand its impact on STI spread, more and better quality data on frequency of unprotected AI, and trends over time are required.

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Efficacy dilution in randomized placebo-controlled vaginal microbicide trials

Cited by 61 publications

References 19 publications

Assessing the Reporting of Adherence and Sexual Activity in a Simulated Microbicide Trial in South Africa: An Interview Mode Experiment Using a Placebo Gel

Assessing the Reporting of Adherence and Sexual Activity in a Simulated Microbicide Trial in South Africa: An Interview Mode Experiment Using a Placebo Gel

Anal Sex, Vaginal Practices, and HIV Incidence in Female Sex Workers in Urban Kenya: Implications for the Development of Intravaginal HIV Prevention Methods

Prevalence and Frequency of Heterosexual Anal Intercourse Among Young People: A Systematic Review and Meta-analysis

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