Background and objectives: Sexual behavior following voluntary HIV counseling and testing (VCT) is described in 963 cohabiting heterosexual couples with one HIV positive and one HIV negative partner (`discordant couples'). Biological markers were used to assess the validity of self-report.
Methods: Couples were recruited from a same-day VCT center in Lusaka, Zambia. Sexual exposures with and without condoms were recorded at 3-monthly intervals. Sperm detected on vaginal smears, pregnancy, and sexually transmitted diseases (STD) including HIV, gonorrhea, syphilis, and Trichomonas vaginalis were assessed.
Results: Less than 3% of couples reported current condom use prior to VCT. In the year after VCT, > 80% of reported acts of intercourse in discordant couples included condom use. Reporting 100% condom use was associated with 39–70% reductions in biological markers; however most intervals with reported unprotected sex were negative for all biological markers. Under-reporting was common: 50% of sperm and 32% of pregnancies and HIV transmissions were detected when couples had reported always using condoms. Positive laboratory tests for STD and reported extramarital sex were relatively infrequent. DNA sequencing confirmed that 87% of new HIV infections were acquired from the spouse.
Conclusions: Joint VCT prompted sustained but imperfect condom use in HIV discordant couples. Biological markers were insensitive but provided evidence for a significant under-reporting of unprotected sex. Strategies that encourage truthful reporting of sexual behavior and sensitive biological markers of exposure are urgently needed. The impact of prevention programs should be assessed with both behavioral and biological measures.
From the aDepartment of Epidemiology and International Health, School of Public Health, University of Alabama in Birmingham, Birmingham, Alabama USA, bZambia-UAB HIV Research Project (ZUHRP), Lusaka, Zambia, the cCincinnati Children's Medical Center, Cincinnati, OH, USA, the dUniversity Teaching Hospital, Lusaka, Zambia, the eDepartment of Microbiology, School of Medicine, University of Alabama in Birmingham, Birmingham, Alabama USA, fDepartment of Medicine, Duke University Medical Center, Durham, North Carolina, USA, the gTropical Disease Research Centre, Ndola, Zambia, and the hMinistry of Health Counseling Unit, Chainama Hills Hospital, Lusaka, Zambia.
Correspondence to S. Allen, Associate Professor of Epidemiology and International Health, School of Public Health, University of Alabama at Birmingham, 933 19th St South #311, Birmingham, AL 35294, USA.
Received: 31 January 2002; revised: 20 September 2002; accepted: 8 October 2002.