ANTIRETROVIRAL TREATMENT OF MEN INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 REDUCES THE INCIDENCE OF HETEROSEXUAL TRANSMISSION

Objective: To determine the incidence of heterosexual human immunodefi ciency virus type 1 disease transmission and the effect of zidovudine therapy on this risk of transmission. Design: A cohort of 436 monogamo us seronegative female sexual partners of human immunodeficiency virus type 1-infected males was followed up for 740 person-years with regul ar structured interviews and laboratory tests. Patients: At enrollment of the women, 50% of their infected partners had one or more signs of disease progression (symptoms of acquired immunodeficiency syndrome, p24 antigen positivity, or CD4+ cell counts lower than 0.4X10(9)/L) an d 15% were treated with zidovudine. Main Outcome Measure: Incidence ra tes of seroconversion were calculated and relative risks were estimate d as incidence rate ratios. Results: Twenty-seven women seroconverted during follow-up, and the incidence of seroconversion was 3.7 per 100 person-years. Seroconversion was about six times more frequent (relati ve risk, 5.8; 95% confidence interval, 2.2 to 15.3) in couples not usi ng condoms. Men with signs of disease progression transmitted infectio n to their partners more frequently and were more frequently treated w ith zidovudine. When the risk of transmission was estimated accounting for disease progression, the rate of transmission in zidovudine-treat ed men was lower than in untreated men (relative risk, 0.5; 95% confid ence interval, 0.1 to 0.9). Conclusion: Treatment of human immunodefic iency virus type-1 infected men with zidovudine reduces, but does not eliminate, heterosexual transmission of infection. Behavioral counseli ng that encourages sexual practices with a lower risk of transmission remains the most important method of prevention.