ASSESSMENT OF THE CHANGING WILLINGNESS TO PARTICIPATE IN PHASE-III HIV VACCINE TRIALS AMONG MEN WHO HAVE SEX WITH MEN

This paper describes the willingness of 1267 men who have sex with men (MSM) enrolled in a prospective HIV vaccine preparedness study from C hicago, Denver, and San Francisco to enroll in HIV vaccine efficacy tr ials. Respondents were interviewed at baseline and followed-up at 6, 1 2, and 18 months. At each visit respondents mere tested for HIV antibo dies using enzyme-linked immunosorbent assay (ELISA) testing with West ern blot confirmation. Over 18 months, the annualized HIV seroincidenc e of this cohort was 2.4%. At baseline, 37% of the men reported that t hey would be ''definitely'' willing to participate in an HIV vaccine e fficacy trial; however, this dropped to 21% at 12 months and remained stable at 18 months. Greater willingness to participate (WTP) was rela ted to lower education, engaging in HIV risk behavior, Living in Denve r, white ethnicity, and older age. Changing WTP suggests that the deci sion to participate in HIV vaccine efficacy trials may be complex and dynamic and take an extended time. These data underscore the importanc e of informed consent and raise questions regarding the influence of d ecision-making processes on HIV vaccine efficacy trial design, complia nce, and validity.