RISK BEHAVIOR FOR HIV-INFECTION IN PARTICIPANTS IN PREVENTIVE HIV VACCINE TRIALS - A CAUTIONARY NOTE

We conducted a longitudinal study of participants in phase I and II HI V vaccine safety and immunogenicity trials to examine changes in sexua l risk behavior that are associated with risk of HIV transmission. The participants were 48 HIV-negative men and women enrolled in one of tw o placebo-controlled HIV vaccine trials conducted at San Francisco Gen eral Hospital. There was a significant increase in insertive unprotect ed anal intercourse (UAI) from 9% at baseline (trial entry), to 13% at the month 6 assessment, to 20% at the month 12 assessment (p =.02). T he primary predictor of either insertive or receptive UAI during the v accine trials was having engaged in this behavior prior to entry (p =. 001). Higher-risk behavior was also seen among participants who were y ounger and had multiple sexual partners (each, p = .06) and who indica ted that one of their reasons for participation in the vaccine trial w as hope of protection from HIV infection (p =.07). These findings indi cate that, despite instructions otherwise, participants with a history of high-risk behavior or who express hope of protection from HIV infe ction by enrolling in vaccine trials may be candidates for more intens ive risk-behavior counseling prior to and during their participation.