Biological Markers of Sexual Activity

Abstract

Research on interventions to prevent HIV and other sexually transmitted infections (STIs) is heavily influenced by participant reporting of sexual behavior, despite uncertainty about its validity. Exclusive reliance on participant self-report often is based, overtly or by implication, on 4 assumptions: (1) no feasible alternatives exist; (2) misreporting can be minimized to levels that can be disregarded; (3) misreporting tends to underreport sensitive behaviors; and (4) misreporting tends to be nondifferential with respect to the groups being compared. The objective of this review are to evaluate these assumptions, including a review of studies using semen biomarkers to evaluate the validity of self-reported data, and to make recommendations for applying biological markers of semen exposure detectable in women to further strengthen research on HIV/STI prevention. Increasing evidence shows that semen biomarkers provide an important means of assessing and augmenting the validity of studies on HIV/STI prevention. Additional biomarkers are needed to assess male exposure to vaginal sex and both male and female exposure to anal sex. Methods and study designs that incorporate biomarkers into studies collecting self-reported behavioral data should be considered where possible.

Are Hormonal Contraceptive Users More Likely to Misreport Unprotected Sex? Evidence From a Biomarker Validation Study in Zimbabwe

“…Nevertheless, although the discrepancy between biomarker data indicating recent sexual activity and self-reported sexual behavior has been reported previously, 36 this is the first time a validation study comparing biomarker outcomes with self-reported sexual behavior has been conducted within a study that also reported an increased HIV risk associated with injectable HC. Our results provide no evidence to support the hypothesis that differential over-reporting of condom use by HC users constitutes a primary explanation for the association between hormonal contraception use and HIV infection.…”

Prostate-Specific Antigen is Unlikely to Be a Suitable Biomarker of Semen Exposure From Recent Unprotected Receptive Anal Intercourse in Men Who Have Sex With Men

“…Given these self-reports, we detected PSA in substantially fewer men than expected, especially compared to similar work in women (3). Low PSA levels prevented us from performing more sophisticated analyses of discordance (positive PSA despite report of no unprotected sex).…”

“…Valid measurement of sexual behaviors, including RAI, is critical for HIV prevention interventions. Yet, to date, nearly all sexual health research has relied on self-reported data, despite questionable validity (3, 4). Individuals may not accurately report whether, when, and how often they engage in risky behaviors, and research findings based on self-reported information may be biased.…”

Semen says: assessing the accuracy of adolescents' self-reported sexual abstinence using a semen Y-chromosome biomarker

“…Most measures of condom use used in research rely on self-reported sexual behaviour rather than biomarkers, despite known inaccuracies in self-report. 1 Researchers may use questions about sexual behaviour as screening items for condom use questions and discard non-respondents from analysis. To decrease reliance on self-report, researchers have used semen exposure biomarkers in studies of HIV prevention 1 and recurrent bacterial vaginosis.…”

“…1 Researchers may use questions about sexual behaviour as screening items for condom use questions and discard non-respondents from analysis. To decrease reliance on self-report, researchers have used semen exposure biomarkers in studies of HIV prevention 1 and recurrent bacterial vaginosis. 2 This study evaluated whether adolescent respondents who reported abstinence from vaginal sex would test negative for the semen Y-chromosome biomarker.…”