Objective: To describe risks for HIV transmission from male blood donors to their regular female sex partners in Chiang Mai, Thailand.
Design: Cross-sectional study.
Methods: From March 1992 through September 1995, 405 HIV-seropositive male blood donors (index cases) and their regular female partners were enrolled in the study. Women with risk factors for HIV infection other than sexual contact with the index male were excluded. Couples were interviewed and examined; specimens were collected for laboratory analysis.
Results: Overall, 46% of the 405 women enrolled were HIV-positive. Ninety-eight per cent of male index cases had a history of sex with a female prostitute; 1.5% reported always using condoms with their regular partner. History of sexually transmitted disease (STD) and swollen inguinal lymph nodes in the female partner were associated with an increased risk of HIV infection in the female. History in the female of genital herpes [odds ratio (OR), 3.46; 95% confidence interval (CI), 1.50-8.78], gonorrhea or chlamydia infection (OR, 2.71; 95% CI, 1.39-5.53), and stable relationship of longer than 24 months (OR, 2.28; 95% CI, 1.02-5.09) were associated with an increased risk of HIV infection in the female. Consistent condom use in the past 2 years (OR, 0.10; 95% CI, 0.01-0.79) was associated with a decreased risk of HIV infection in the female.
Conclusions: Married women in northern Thailand who appear otherwise to be at low risk for HIV infection may be exposed to this virus by their husbands. High rates of sex with commercial sex workers among men and low use of condoms within stable relationships may be important factors promoting the transmission of HIV in married couples. Programs to increase the regular use of condoms among married couples could be an important public health intervention to prevent transmission of HIV and other types of STD in northern Thailand.
PIP: The risk factors for HIV transmission from infected male blood donors to their regular female sex partners were investigated in a cross-sectional study conducted in Chiang Mai, Thailand, in 1992-95. During the 3.5-year study period, 405 couples were recruited. 98% of male blood donors reported a history of sex with female prostitutes. Only 28 men (7%) were aware of their seropositivity prior to notification by the blood bank, and just 1.5% always used condoms with their regular sex partner. 187 (46%) of the 405 female sex partners--none of whom had HIV risk factors other than sexual contact with their husbands--were HIV-positive at baseline. In the multivariate analysis, three variables were associated with a significantly increased risk of HIV in female partners: history of genital herpes (odds ratio (OR), 3.46; 95% confidence interval (CI), 1.50-8.78), history of gonorrhea or chlamydia (OR, 2.71; 95% CI, 1.39-5.53), and a stable relationship of at least 2 years' duration (OR, 2.28; 95% CI, 1.02-5.09); consistent condom use in the past 2 years was significantly associated with a decreased risk of HIV (OR, 0.10; 95% CI, 0.01-0.79). Medroxyprogesterone acetate injection and oral contraceptive use were not associated with HIV risk. These findings confirm a high risk of HIV transmission through monogamous sexual relationships in Thailand. Recommended are campaigns to increase regular condom use among married couples.