Condom use and vaginal Y-chromosome detection: the specificity of a potential biomarker

A Comparison of Self-reported Condomless Sex and Yc-DNA Biomarker Data from Young Women Engaged in High Risk Sexual Activity in Kampala, Uganda

Reporting of condom-use can limit researchers' understanding of high-risk sexual behaviours. We compared self-reported condom-use with the Yc-DNA biomarker data and investigated potential factors influencing participation in, and reporting of, sexual behaviours. Self-reported data were collected using Audio Computer Assisted Self Interviews (ACASI) and samples for Yc-DNA biomarker were collected using self-administered and health worker-collected vaginal swabs from 644 women (aged 15-24 years) who were not living with HIV. Yc-DNA results and interview data were compared using McNemar-Bowker Analysis and Cohen's Kappa. Test statistics for Yc-DNA biomarker were calculated. Log Binomial models for Yc-DNA and self-reported results were conducted to assess for association. We found strong evidence (p < 0.001) for a difference between Yc-DNA and self-reported results. 13.7% of participants reported consistent condom-use with all partners, regardless of HIV status. Self-reported condom-use was discordant in 50.0% (n = 206) of cases, when compared to Yc-DNA results. Positive Yc-DNA results were found to be associated with older age (RR 1.36; 95%CI 1.04, 1.76 p = 0.023). Self-reported condom-use with partners with unknown HIV status was associated with higher education (RR 0.76; 95%CI 0.58,0.99 p = 0.043). Sensitivity analysis did not determine difference between methods for controlling for missing data. We found significant under-reporting of condomless sex in the self-reported data when compared to Yc-DNA results.

Semen: A modulator of female genital tract inflammation and a vector for HIV-1 transmission

In order to establish productive infection in women, HIV must transverse the vaginal epithelium and gain access to local target cells. Genital inflammation contributes to the availability of HIV susceptible cells at the female genital mucosa and is associated with higher HIV transmission rates in women. Factors that contribute to genital inflammation may subsequently increase the risk of HIV infection in women. Semen is a highly immunomodulatory fluid containing several bioactive molecules with the potential to influence inflammation and immune activation at the female genital tract. In addition to its role as a vector for HIV transmission, semen induces profound mucosal changes to prime the female reproductive tract for conception. Still, most studies of mucosal immunity are conducted in the absence of semen or without considering its immune impact on the female genital tract. This review discusses the various mechanisms by which semen exposure may influence female genital inflammation and highlights the importance of routine screening for semen biomarkers in vaginal specimens to account for its impact on genital inflammation.

Inconsistent Sexual Behavior Reporting Among Youth Affected by Perinatal HIV Exposure in the United States

We examined reporting agreement of oral, vaginal, and anal sex in adolescents and young adults living with perinatally-acquired HIV and those perinatally HIV-exposed and uninfected in the Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol (AMP) and AMP Up studies. Agreement between fixed constructs (e.g., age at first sex) and prevalence of logical inconsistencies (e.g., reclaimed virginity status) over time were assessed. Internal consistency was also examined using an attention check question and questions regarding condom use in the prior three months. Those who reported having anal sex in adolescence had a higher proportion of inconsistent responses compared to vaginal and oral sex measures. At their most recent survey, 84% of young adults correctly answered an attention check question and 74% agreed within the survey on condom use in the prior three months. In bivariate analyses, HIV status was not associated with responding inconsistently. Increased time between surveys, male sex, and younger age at first survey were associated with multiple measures of inconsistency over time, while lower cognitive scores, having less than a high school diploma, and negatively answering post-survey acceptability questions were associated with incorrectly answering an attention check question.

HIV-1 Nucleic Acids Identify Rectal HIV Exposures in Self-Collected Rectal Swabs, Whereas Y-Chromosome Single Tandem Repeat Mixtures Are Not Reliable Biomarkers of Condomless Receptive Anal Intercourse

BACKGROUND

To focus interventions, biomarkers of HIV-1 exposure could help in identifying subpopulations at highest risk of acquisition. We assessed whether Y-chromosome single tandem repeat (YSTR) mixtures obtained from rectal swabs could serve as a biomarker of condomless receptive anal intercourse (CRAI) among men who have sex with men and transgender women and evaluated the feasibility of detecting HIV-1 virions to assess exposures.

METHODS

Twenty-nine sexually active HIV-seronegative men who have sex with men and one transgender woman from New York City answered on-site and mobile app sexual behavior questionnaires. They were randomized to collecting self-administered rectal swabs every morning or after receptive anal intercourse (RAI). YSTR profiles were assessed from blood sample and swabs; HIV-1 exposure was measured by conducting quantitative polymerase chain reaction in swabs.

RESULTS

After 2 months, the daily mobile survey had 135%-201% more instances of anal sex acts and 170%-193% more RAI than on-site surveys. Daily mobile reporting had 11%-35% less CRAI events than those reported on-site (Pdaily = 0.001; Pper-sex = 0.047). The daily swabbing arm reported less RAI (P < 0.001) and CRAI (P < 0.038) and had 2.95 lower odds of detecting YSTR mixtures (P = 0.021) than the per-sex-event arm. Surprisingly, YSTR detection was not significantly modified by report of bowel movements and lubricant, enema, or condom use. No participant became HIV-1 infected, yet HIV-1 total nucleic acids were detected in 6 independent episodes of CRAI in 2 participants taking pre-exposure prophylaxis.

CONCLUSIONS

YSTR mixtures demonstrated 80% specificity but only 30% sensitivity as a biomarker of CRAI in self-collected rectal swabs. However, detection of HIV-1 exposures in self-collected swabs may help in identifying those needing further HIV risk reduction strategies.

Trends in Reported Sexual Behavior and Y-Chromosomal DNA Detection Among Female Sex Workers in the Senegal Preexposure Prophylaxis Demonstration Project

A study among female sex workers in Senegal found no evidence of increased sexual risk behavior after preexposure prophylaxis initiation as measured by self-report or Y-chromosomal DNA detection.

Supplemental digital content is available in the text.

Background

Preexposure prophylaxis (PrEP) can reduce HIV acquisition among female sex workers (FSWs). However, changes in condomless sex frequency after PrEP initiation could reduce PrEP effectiveness when PrEP adherence is suboptimal as well as increase the risk of acquiring other sexually transmitted infections. Objective measures of condomless sex may be more accurate for determining changes in sexual behavior than self-reported measures.

Methods

We longitudinally measured self-reported condom use, number of clients, and presence of Y-chromosomal DNA (Yc-DNA) in vaginal swabs among 267 FSWs accessing PrEP at 4 clinics in Senegal between 2015 and 2016. We assessed trends in sexual behavior over time since PrEP initiation using generalized estimating equations and evaluated predictors of Yc-DNA detection.

Results

We found no increase in self-reported condomless sex with clients (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.89–1.00), main partners (OR, 0.99; 95% CI, 0.96–1.02), or Yc-DNA detection (OR, 0.99; 95% CI, 0.90–1.08) over time since initiation. Y-chromosomal DNA was detected in 34 (22%) of 154 swabs tested and in 15 (26%) of 58 swabs from FSW reporting consistent condom use among both clients and main partners. Self-reported condom use with clients or main partners did not predict Yc-DNA detection.

Conclusions

In a FSW PrEP demonstration project in Senegal, we found no evidence of risk compensation among FSWs on PrEP as measured by self-reported behavior or through Yc-DNA detection. Y-chromosomal DNA detection was frequently detected among FSWs reporting consistent condom use, highlighting limitations of self-reported sexual behavioral measures.

Y Chromosome DNA in Women's Vaginal Samples as a Biomarker of Recent Vaginal Sex and Condom Use With Male Partners in the HPV Infection and Transmission Among Couples Through Heterosexual Activity Cohort Study

BACKGROUND

Y chromosome DNA from male epithelial and sperm cells was detected in vaginal samples after unprotected sex in experimental studies. We assessed the strength of this association in an observational setting to examine the utility of Y chromosome DNA as a biomarker of recent sexual behaviors in epidemiological studies.

METHODS

The HPV (human papillomavirus) Infection and Transmission Among Couples Through Heterosexual Activity cohort study enrolled 502 women attending a university or college in Montréal, Canada, and their male partners from 2005 to 2010. Participants completed self-administered questionnaires. We used real-time polymerase chain reaction to test women's baseline vaginal samples for Y chromosome DNA and assessed which sexual behaviors were independent predictors of Y chromosome DNA positivity and quantity with logistic and negative binomial regression.

RESULTS

Y chromosome DNA positivity decreased from 77% in women in partnerships reporting vaginal sex 0 to 1 day ago to 13% in women in partnerships reporting last vaginal sex of 15 or more days ago (adjusted odds ratio, 0.09; 95% confidence interval, 0.02-0.36). The mean proportion of exfoliated vaginal sample cells with Y chromosome DNA was much lower for women who reported always using condoms (0.01%) than for women who reported never using condoms (2.07%) (adjusted ratio, 26.8; 95% confidence interval, 8.9-80.5). No association was found with reported oral/digital sex frequency or concurrency of partnerships.

CONCLUSIONS

Y chromosome DNA quantity is strongly associated with days since last vaginal sex and lack of condom use in observational settings. Y chromosome DNA quantity may prove useful as a correlate of recent vaginal sex in observational studies lacking data on sexual behavior, such as surveillance studies of human papillomavirus infection prevalence.

Test-Retest Reliability of Self-Reported Sexual Behavior History in Urbanized Nigerian Women

BACKGROUND

Studies assessing risk of sexual behavior and disease are often plagued by questions about the reliability of self-reported sexual behavior. In this study, we evaluated the reliability of self-reported sexual history among urbanized women in a prospective study of cervical HPV infections in Nigeria.

METHODS

We examined test-retest reliability of sexual practices using questionnaires administered at study entry and at follow-up visits. We used the root mean squared approach to calculate within-person coefficient of variation (CVw) and calculated the intra-class correlation coefficient (ICC) using two way, mixed effects models for continuous variables and [Formula: see text] statistics for discrete variables. To evaluate the potential predictors of reliability, we used linear regression and log binomial regression models for the continuous and categorical variables, respectively.

RESULTS

We found that self-reported sexual history was generally reliable, with overall ICC ranging from 0.7 to 0.9; however, the reliability varied by nature of sexual behavior evaluated. Frequency reports of non-vaginal sex (agreement = 63.9%, 95% CI: 47.5-77.6%) were more reliable than those of vaginal sex (agreement = 59.1%, 95% CI: 55.2-62.8%). Reports of time-invariant behaviors were also more reliable than frequency reports. The CVw for age at sexual debut was 10.7 (95% CI: 10.6-10.7) compared with the CVw for lifetime number of vaginal sex partners, which was 35.2 (95% CI: 35.1-35.3). The test-retest interval was an important predictor of reliability of responses, with longer intervals resulting in increased inconsistency (average change in unreliability for each 1 month increase = 0.04, 95% CI = 0.07-0.38, p = 0.005).

CONCLUSION

Our findings suggest that overall, the self-reported sexual history among urbanized Nigeran women is reliable.

Predicting Unprotected Sex and Unplanned Pregnancy among Urban African-American Adolescent Girls Using the Theory of Gender and Power

Reproductive coercion has been hypothesized as a cause of unprotected sex and unplanned pregnancies, but research has focused on a narrow set of potential sources of reproductive coercion. We identified and evaluated eight potential sources of reproductive coercion from the Theory of Gender and Power including economic inequality between adolescent girls and their boyfriends, cohabitation, and age differences. The sample comprised sexually active African-American female adolescents, ages 15-21. At baseline (n = 715), 6 months (n = 607), and 12 months (n = 605), participants completed a 40-min interview and were tested for semen Y-chromosome with polymerase chain reaction from a self-administered vaginal swab. We predicted unprotected sex and pregnancy using multivariate regression controlling for demographics, economic factors, relationship attributes, and intervention status using a Poisson working model. Factors associated with unprotected sex included cohabitation (incidence risk ratio (IRR) 1.48, 95 % confidence interval (1.22, 1.81)), physical abuse (IRR 1.55 (1.21, 2.00)), emotional abuse (IRR 1.31 (1.06, 1.63)), and having a boyfriend as a primary source of spending money (IRR 1.18 (1.00, 1.39)). Factors associated with unplanned pregnancy 6 months later included being at least 4 years younger than the boyfriend (IRR 1.68 (1.14, 2.49)) and cohabitation (2.19 (1.35, 3.56)). Among minors, cohabitation predicted even larger risks of unprotected sex (IRR 1.93 (1.23, 3.03)) and unplanned pregnancy (3.84 (1.47, 10.0)). Adolescent cohabitation is a marker for unprotected sex and unplanned pregnancy, especially among minors. Cohabitation may have stemmed from greater commitment, but the shortage of affordable housing in urban areas could induce women to stay in relationships for housing. Pregnancy prevention interventions should attempt to delay cohabitation until adulthood and help cohabiting adolescents to find affordable housing.

Assessment of the vaginal residence time of biomarkers of semen exposure

OBJECTIVE

The primary objective of this pilot study is to determine and compare the residence time in the vagina of biomarkers of semen exposure for up to 15 days post exposure. The biomarkers are prostate-specific antigen (PSA), Y chromosome DNA, the sex determining region of the Y chromosome (SRY) and testis-specific protein Y-encoded 4 (TSPY4). The secondary objectives are to determine if biomarker concentrations differed between intercourse and inoculation groups, to establish whether the sampling frequency post exposure affected biomarker concentrations and decay profile and to determine if biomarker concentrations in vaginal swabs obtained by the participant at home were similar to swabs obtained by the nurse in the clinic.

STUDY DESIGN

We randomized healthy women to unprotected intercourse (n=17) versus vaginal inoculation with the male partner's semen in the clinic (n=16). Women were then further randomized to have vaginal swabs obtained at either 7 or 4 time points after semen exposure, up to 15 days post exposure, either obtained at home by the participant or in the clinic by the research nurse.

RESULTS

PSA and SRY were markers of recent semen exposure. TSPY4 was detectable in approximately 50% of participants at 15 days post exposure. Unprotected intercourse resulted in significantly higher concentrations of select biomarkers. Sampling frequency and home versus clinic sampling had no significant effect on biomarker concentrations.

CONCLUSIONS

Objective biomarkers of recent or distant semen exposure may have great utility for verifying protocol compliance in a variety of clinical trials.

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

OBJECTIVE

Researchers often assess condom use only among participants who report recent sexual behaviour, excluding participants who report no recent vaginal sex or who did not answer questions about their sexual behaviour, but self-reported sexual behaviour may be inaccurate. This study uses a semen Y-chromosome biomarker to assess semen exposure among participants who reported sexual abstinence or did not report their sexual behaviour.

METHODS

This prospective cohort study uses data from 715 sexually active African-American female adolescents in Atlanta, surveyed at baseline, 6 months and 12 months. Participants completed a 40 min interview and were tested for semen Y-chromosome with PCR from a self-administered vaginal swab. We predicted Y-chromosome test results from self-reported sexual behaviour using within-subject panel regression.

RESULTS

Among the participants who reported abstinence from vaginal sex in the past 14 days, 9.4% tested positive for semen Y-chromosome. Among item non-respondents, 6.3% tested positive for semen Y-chromosome. Women who reported abstinence and engaged in item non-response regarding their sexual behaviour had respectively 62% and 78% lower odds of testing positive for Y-chromosome (OR 0.38 (0.21 to 0.67), OR 0.22 (0.12 to 0.40)), controlling for smoking, survey wave and non-coital sexual behaviours reported during abstinence.

CONCLUSIONS

Adolescents who report sexual abstinence under-report semen exposure. Research should validate self-reported sexual behaviour with biomarkers. Adolescents who engage in item non-response regarding vaginal sex test positive for semen Y-chromosome at similar rates, which supports the practice of grouping non-respondents with adolescents reporting abstinence in statistical analysis.

TRIAL REGISTRATION NUMBER

NCT00633906.

INSTRUMENTS OF HIGH RISK SEXUAL BEHAVIOR ASSESSMENT: A SYSTEMATIC REVIEW

BACKGROUND

Sexual behavior is a complex activity affecting all aspects of human's life. Risky sexual behaviors impose negative outcomes on family, relationships and health. Unsafe sex is the second most leading cause of disability adjusted life years worldwide. Valid and reliable tools for assessment of risky sexual behaviors are necessary for implementing preventive measures.

METHODS

we searched Medline and the Cochrane Library of Systematic Reviews, with the keywords of "risky sexual behavior assessment", "sexual risk assessment", "high risk sexual behavior", "sexual risk taking". By reviewing references of the articles, some complementary studies were added.

RESULTS

Assessment can be performed by questionnaire or non-questionnaire instruments. Questionnaires vary depending on their target population, evaluation of risky sexual behavior as a whole or focusing on an associated risk factor. In order to avoid usual biases in self reports, objective biomarker assessment of unprotected sex are employed. These markers include prostate specific antigen, chromosome Y DNA and Seminogelin.

CONCLUSION

Risky sexual behavior can be assessed by various subjective and objective methods. While self-reports are more feasible, objective methods offer a higher degree of reliability. Further studies for finding more feasible methods of using biomarkers are recommended.

Y chromosome DNA in cervicovaginal self-collected samples of childbearing age women: Implications for epitheliotropic sexually transmitted infections?

AIMS

Assuming a possible association between Y chromosome (Yc)-DNA and sexually transmitted infection (STI) transmission rate, could Yc-DNA be related to an increased prevalence of Human Papillomavirus (HPV), Herpes Simplex Virus (HSV-1/2) and Chlamydia trachomatis (CT)? Could Yc-DNA be used to validate self-reported condom use and sexual behaviors?

MAIN METHODS

Cervicovaginal (CV) self-collected samples of 612 Portuguese women at childbearing age were tested for Yc, HPV, HSV-1/2 and CT by polymerase chain reaction (PCR).

KEY FINDINGS

The prevalence of Yc, HPV, CT and HSV-2 was 4.9%, 17.6%, 11.6% and 2.8%, respectively. There was a statistically significant trend for increased Yc-DNA prevalence in HPV positive samples [odds ratio (OR) 2.35, 95% confidence interval (CI) 1.03-5.31] and oral contraceptive (OC) use (OR 4.73, 95% CI 1.09-20.44). A protective effect of condom use was observed in Yc-DNA detection (OR 0.40, 95% CI 0.18-0.89). No statistically significant difference was found between Yc-DNA, CT and HSV-2 infection. HPV infection risk increased with age (>20 years), young age at first sexual intercourse (FSI) (≤18 years), >1 lifetime sexual partner (LSP) and OC use. Risk factors for CT infection were young age (≤20 years) and young age at FSI (≤18 years). HSV-2 infection risk increased with age (>20 years) and >1 LSP.

SIGNIFICANCE

Considering the prevalence of HPV and CT in Yc positive samples, we hypothesize a current infection due to recent sexual activity. The study of Yc PCR may add information as (i) a predictor of STI transmission and (ii) an indicative biomarker to validate self-reported condom use.

Y chromosome and HIV DNA detection in vaginal swabs as biomarkers of semen and HIV exposure in women

BACKGROUND

The inability to quantify sexual exposure to HIV limits the power of HIV prevention trials of vaccines, microbicides, and preexposure prophylaxis in women. We investigated the detection of HIV-1 and Y chromosomal (Yc) DNA in vaginal swabs from 83 participants in the HPTN 035 microbicide trial as biomarkers of HIV exposure and unprotected sexual activity.

METHODS

One hundred forty-three vaginal swabs from 85 women were evaluated for the presence of Yc DNA (Quantifiler Duo DNA quantification kit; Applied Biosystems) and total HIV-1 DNA (single-copy in-house quantitative polymerase chain reaction assay). Y DNA detection was paired with self-reported behavioral data with regard to recent coitus (≤1 week before collection) and condom usage (100% vs. <100% compliance).

RESULTS

Yc DNA was detected in 62 (43%) of 143 swabs. For the 126 visits at which both behavioral data and swabs were collected, Yc DNA was significantly more frequent in women reporting less than 100% condom usage (odds ratio, 10.69; 95% confidence interval, 2.27-50.32; P = 0.003). Notably, 27 (33%) of 83 swabs from women reporting 100% condom usage were positive for Yc DNA. HIV DNA was only detected in swabs collected postseroconversion.

CONCLUSIONS

The use of Yc DNA in HIV prevention trials could reliably identify subgroups of women who have unprotected sexual activity and could provide valuable exposure-based estimates of efficacy.

Differences in sexual risk behaviors between lower and higher frequency alcohol-using African-American adolescent females

BACKGROUND

To examine differences between lower and higher frequency alcohol users in sexual behaviors and psychosocial correlates of risk for HIV among young African-American females.

METHODS

Data were collected from sexually active African-American females aged 15-20 years, seeking services at a STD clinic in Atlanta, GA, to assess sexual behavior, correlates of risk, and a non-disease biological marker of unprotected vaginal sex.

RESULTS

Number of drinking occasions was significantly related to three of four psychosocial correlates and with all self-reporting sexual behavior measures. Also, heavier drinking per occasion was associated with the presence of semen in vaginal fluid.

CONCLUSION

Non-abuse levels of drinking were related to increased sexual risk-taking in this sample of young African- American females. Incorporating messages about the intersection of alcohol use and sexual decision making into HIV/STD prevention programs would strengthen STD prevention messaging in this vulnerable population.

The use of biomarkers of semen exposure in sexual and reproductive health studies

Biomarkers of semen exposure have been used in studies investigating the safety and efficacy of barrier methods of contraception. They have been used as objective indicators of semen exposure when studying sexual behaviors and in human immunodeficiency virus/sexually transmitted infection research interventions where participants are advised to avoid unprotected sex. Semen biomarkers have also been used to assess or validate self-reported sexual behaviors or condom use in reproductive health settings. Prostate-specific antigen (PSA) and Y chromosome DNA (Yc-DNA) have each been evaluated in the past as semen biomarkers and are the most widely used in the field. While both are considered reliable for evaluating exposure to semen, each has unique characteristics. In this report, we summarize the literature and provide some considerations for reproductive health researchers who are interested in using PSA or Yc-DNA as semen biomarkers. We also synthesize our previous published work on the optimal conditions of collecting and storing specimens and assay performance in the presence of other vaginal products that may influence various assays. Semen biomarkers are innovative and promising tools to further study and better understand women's reproductive and sexual health and behavior. More research is needed to better understand the strengths, limitations, and optimal performance conditions of specific assays in vivo.

Validity of behavioral measures as proxies for HIV-related outcomes

Over the last 30 years, expectations for the quality, validity, and objectivity of the outcome measures used to assess the impact of behavior change interventions related to HIV have steadily increased. At this point (mid-2014 at this writing), biologic evidence or biomarkers of the incidence of HIV and other sexually transmitted infections in a target population is clearly preferable to self-reports of behavior. This kind of evidence is, however, much more expensive to collect than participants' reports of behavior change (eg, increased condom use, reduced substance use or abstinence from substance use, and high levels of medication adherence). In addition, although potentially less subject to reporting bias, biomarkers and biologic outcomes have their own flaws. In this article, we review the literature on the validity of self-reports of outcomes most relevant to HIV behavior change interventions, sexual behavior (ever having had sex and condom use), substance use, and medication adherence. We note the extent to which they may be adequate outcome measures without biologic data, and the conditions under which they may be most likely to be sufficient. We also argue, like many others, that where possible, both self-report and biologic measures should be collected.

Does tenofovir gel or do other microbicide products affect detection of biomarkers of semen exposure in vitro?

OBJECTIVES

There is currently no information on whether products evaluated in HIV microbicide trials affect the detection of the semen biomarkers prostate-specific antigen (PSA) or Y chromosome DNA.

STUDY DESIGN

We tested (in vitro) dilutions of tenofovir (TFV), UC781 and the hydroxyethylcellulose (HEC) placebo gels using the Abacus ABAcard and the quantitative (Abbott Architect total PSA) assays for PSA and Y chromosome DNA by real-time polymerase chain reaction.

RESULTS

TFV gel and the HEC placebo adversely affected PSA detection using the ABAcard but not the Abbott Architect total PSA assay. UC781 adversely affected both the ABAcard and Abbott Architect total PSA assays. While there were some quantitative changes in the magnitude of the signal, none of the products affected positivity of the Y chromosome assay.

CONCLUSIONS

The presence of TFV or HEC gels did not affect quantitative PSA or Y chromosome detection in vitro. Confirmation of these findings is recommended using specimens obtained following use of these gels in vivo.

IMPLICATIONS

Researchers should consider the potential for specific microbicides or any products to affect the particular assay used for semen biomarker detection. The ABAcard assay for PSA detection should not be used with TFV UC781, or HEC.

Telling truth from Ys: an evaluation of whether the accuracy of self-reported semen exposure assessed by a semen Y-chromosome biomarker predicts pregnancy in a longitudinal cohort study of pregnancy

OBJECTIVES

Adolescents may use condoms inconsistently or incorrectly, or may over-report condom use. This study used a semen exposure biomarker to evaluate the accuracy of female adolescents' reports of condom use and predict subsequent pregnancy.

METHODS

The sample comprised 715 sexually active African-American female adolescents, ages 15-21 years. At baseline, 6 months and 12 months, participants completed a 40-min interview and were tested for semen Y-chromosome with PCR from a self-administered vaginal swab. We predicted pregnancy from semen exposure under-report using multivariate regression controlling for oral contraception, reported condom use and coital frequency.

RESULTS

At the 3 surveys, 30%, 20% and 15% of adolescents who reported always using condoms tested positive for semen exposure. At 6 month follow-up, 20.4% and 16.2% of the adolescents who under-reported semen exposure reported pregnancy, a higher pregnancy rate than accurate reporters of semen exposure, even accurate reporters who reported never using condoms (14.2% and 11.8%). Under-reporters of semen exposure were 3.23 (95% CI (1.61, 6.45)) times as likely to become pregnant at 6-month follow-up and 2.21 (0.94, 5.20) times as likely to become pregnant at 12-month follow-up as accurate reporters who reported not using contraception, adjusting for self-reported coital frequency.

CONCLUSIONS

Adolescents who under-report semen exposure may be at uniquely high risk for unplanned pregnancy and STIs, and may also under-report coital frequency. Condom efficacy trials that rely on self-report may yield inaccurate results. Adapted to a clinical setting, the Y-chromosome PCR could alert women to incorrect or inconsistent condom use.

Do Jobs Work? Risk and Protective Behaviors Associated with Employment Among Disadvantaged Female Teens in Urban Atlanta

Adolescent employment predicts lower educational engagement and achievement and greater engagement with risk behaviors. Most research has studied middle class rather than disadvantaged adolescents. We identified risk and protective behaviors associated with employment using data from a 3-wave, 12-month study of 715 low-socio-economic status female African American adolescents who were ages 15-21 at baseline. Adolescents who were employed at wave 2 (n=214) were matched with adolescents who were not employed at wave 2 (n=422) using nearest-neighbor matching on baseline factors within propensity score calipers on factors including marijuana use, sex while high, pregnancy risk, and socioeconomic status. We compared employed and non-employed teens on risk behaviors including marijuana use, sex while high or drunk, and a biomarker for semen exposure in the past 14 days. Employed teens were 44% as likely to say that their boyfriend is their primary spending money source and 43% as likely to be emotionally abused, but these benefits did not persist after employment ended. Six months after employment, employed respondents reported using marijuana 57% more often and had sex while drunk or high 2.7 times as frequently. Women who were employed at both waves 2 and 3 were 17% as likely to have their boyfriend as a primary source of spending money and 13% more likely to graduate high school, but they used marijuana twice as often, alcohol 1.6 times as often, had 1.6 times as many sexual partners, and had sex while high or drunk 2.3 times as often. Female teens who work may avoid potentially coercive romantic relationships, but they may buy drugs or alcohol with their earnings.

A cohort study of Chlamydia trachomatis treatment failure in women: a study protocol

BACKGROUND

Chlamydia trachomatis is the most commonly diagnosed bacterial sexually transmitted infection in the developed world and diagnosis rates have increased dramatically over the last decade. Repeat infections of chlamydia are very common and may represent re-infection from an untreated partner or treatment failure. The aim of this cohort study is to estimate the proportion of women infected with chlamydia who experience treatment failure after treatment with 1 gram azithromycin.

METHODS/DESIGN

This cohort study will follow women diagnosed with chlamydia for up to 56 days post treatment. Women will provide weekly genital specimens for further assay. The primary outcome is the proportion of women who are classified as having treatment failure 28, 42 or 56 days after recruitment. Comprehensive sexual behavior data collection and the detection of Y chromosome DNA and high discriminatory chlamydial genotyping will be used to differentiate between chlamydia re-infection and treatment failure. Azithromycin levels in high-vaginal specimens will be measured using a validated liquid chromatography-tandem mass spectrometry method to assess whether poor azithromycin absorption could be a cause of treatment failure. Chlamydia culture and minimal inhibitory concentrations will be performed to further characterize the chlamydia infections.

DISCUSSION

Distinguishing between treatment failure and re-infection is important in order to refine treatment recommendations and focus infection control mechanisms. If a large proportion of repeat chlamydia infections are due to antibiotic treatment failure, then international recommendations on chlamydia treatment may need to be re-evaluated. If most are re-infections, then strategies to expedite partner treatment are necessary.

An evaluation of methods to improve the reporting of adherence in a placebo gel trial in Andhra Pradesh, India

Female sex workers (FSWs) were recruited for a 4-month placebo vaginal gel trial in Nellore, India. Two experiments explored if prior knowledge of biomarkers for unprotected sex and insertion of gel applicators would yield more accurate self-reports. A third experiment compared self-reports of gel use and adherence levels between FSWs randomly assigned to interactive voice response survey (IVRS) and those assigned to paper diaries. Prior knowledge of biomarkers did not improve accuracy of self-reported condom or gel use, nor did it affect actual adherence. Of those who tested positive for the presence of semenogelin in the vagina, 76% reported no unprotected sex in the previous 48 h. Overall, women reported using gel on 90% of days whereas the biomarker indicated gel use on fewer than 50% of days. Compliance to IVRS was low, despite familiarity with mobile phone technology. Additional explorations with other populations are needed.

Optimal methods for collecting and storing vaginal specimens for prostate-specific antigen testing in research studies

BACKGROUND

Prostate-specific antigen (PSA) detected in vaginal fluid can be used in studies of HIV/sexually transmitted infection (STI) and pregnancy prevention as an alternative to relying on participant reports of exposure to semen. Optimal methods for collecting and storing specimens for this testing have not been determined.

STUDY DESIGN

We conducted a controlled, in vitro experiment of 550 specimens spiked with semen to determine the effects of swab type (five types), storage conditions of the swabs (room temperature with or without desiccant or at -80°C without desiccant) and time from collection to testing (seven intervals over the course of 12 months) on the identification of PSA. We performed factorial analysis of variance to identify factors influencing PSA detection.

RESULTS

Concentrations of PSA detected in the swabs declined with time of storage over the 1-year experiment (p<.01). The 1-mL, rayon-tipped swab stored immediately at -80°C following collection performed best.

CONCLUSIONS

If immediate testing or freezer storage is not feasible, investigators should use a swab with 1-mL capacity with processing and testing as soon as possible after specimen collection.

Biological validation of self-reported condom use among sex workers in Guinea

Self-reported condom use may be prone to social desirability bias. Our aim was to assess the validity of self-reported condom use in a population of female sex workers using prostate specific antigen (PSA) as a gold standard biomarker of recent unprotected vaginal intercourse. We collected data on 223 sex-workers in Conakry, Guinea in order to assess the sensitivity and specificity of self-reported condom use as well as to examine the predictors of discordance between self-report and PSA presence. PSA was detected in 38.4% of samples. Sensitivity of self-reported condom use was 14.6% and its specificity was 94.7%. Self-perceived high risk of HIV infection was the only significant independent predictor of misreported condom use. PSA could be useful to validate self-reported condom use in surveys and to allow a better understanding of factors associated with social desirability in sexual behaviour reporting.

Effect of menses on clearance of Y-chromosome in vaginal fluid: implications for a biomarker of recent sexual activity

Self-reported sexual behaviors are subject to bias. We previously developed a polymerase chain reaction for the detection of Y-chromosome sequences in vaginal fluid as a potential biomarker of recent sexual activity. In this study, we found menses results in lower Y-chromosome concentrations but with similar decay patterns as non-menstrual samples.

Vaginal swab specimen processing methods influence performance of rapid semen detection tests: a cautionary tale

BACKGROUND

Detection of semen biomarkers in vaginal fluid can be used to assess women's recent exposure to semen. Quantitative tests for detection of prostate-specific antigen (PSA) perform well, but are expensive and require specialized equipment. We assessed two rapid immunochromatographic strip tests for identification of semen in vaginal swabs.

STUDY DESIGN

We tested 581 vaginal swabs collected from 492 women. Vaginal secretions were eluted into saline, and PSA was measured using the quantitative IMx (Abbott Laboratories, Abbott Park, IL, USA) assay. Specimens were also tested using the ABAcard p30 test (Abacus Diagnostics, West Hills, CA, USA) for detection of PSA and RSID-Semen test (Independent Forensics, Hillside, IL, USA) for detection of semenogelin (Sg).

RESULTS

Vaginal swab extraction using saline was compatible with direct assessment of vaginal swab eluates using ABAcard for PSA detection, but not for Sg detection using RSID. The rapid PSA test detected 91% of specimens containing semen compared to 74% by the rapid Sg test.

CONCLUSION

Investigators are urged to optimize vaginal swab specimen preparation methods for performance of RSID or other tests to detect semen components other than PSA. Previously described methods for PSA testing are not uniformly applicable to other tests.

Biomarkers of semen exposure

Biomarkers of semen exposure have historically played their most important role in forensics, i.e., determining whether ejaculation took place in the course of a crime. However, it is becoming increasingly recognized that biomarkers of semen exposure can be useful in the development of new vaginal methods of HIV/sexually transmitted infections (STI) prevention and contraception. This review is based on the presentations of Drs. Michael Coppola (ContraVac, Inc.), Maurizio Macaluso (Centers for Disease Control and Prevention), Andrezej Kulczycki (University of Alabama at Birmingham), Christine Mauck (CONRAD), Robin Maguire (Population Council), and the subsequent discussion led by Drs. Susan Ballagh (CONRAD) and Johan Melendez (Johns Hopkins University) during a session entitled "Biomarkers of semen exposure" held during the conference entitled "Biomarkers for evaluation of vaginal microbicides and contraceptives: Discovery and early validation," organized by CONRAD and the Alliance for Microbicide Development in November of 2006.