Feasibility of chemoprophylaxis studies in high risk HIV-seronegative populations

Administration of antiretroviral medications-recommended to prevent HIV infection after occupational exposure-has not been evaluated for safety or efficacy following nonoccupational exposure. HIV-seronegative persons at increased risk for HIV exposure completed a self-administered questionnaire assessing their willingness to join studies of this approach. Of 4,572 respondents, 60% were willing to join a study of a "morning-after" pill; dosing three times a day and mild side effects reduced willingness to 30%. Men who have sex with men (MSM) who reported unprotected anal intercourse in the prior 6 months were significantly more likely to be willing to join a morning-after study than MSM who did not (p = 0.006). MSM favored a preventive HIV vaccine over oral chemoprophylaxis; other populations preferred oral chemoprophylaxis. Interest in studies declined as the hypothetical regimen became more demanding. Studies must emphasize the unknown efficacy of this approach, given increased interest among MSM at greater risk of exposure.