“Once Bitten, Twice Shy”: Participant perspectives in the aftermath of an early HIV vaccine trial termination

The Step Study phase IIb HIV-1 vaccine trial was terminated early due to futility; subsequent analyses revealed increased susceptibility to HIV infection among a subset of test vaccine recipients. We conducted a mixed methods investigation, including a brief, self-administered baseline questionnaire and in-depth, semi-structured, 1-h interviews after unblinding, to explore experiences and perspectives among trial participants and key informants. Interviews were digitally recorded, transcribed, and analyzed using NVivo and thematic techniques. Forty-eight trial participants (46 gay/bisexual men) completed baseline surveys; 15 (14 gay/bisexual men) engaged in post-trial interviews. Participants indicated surprise and disappointment about the early trial termination and unexpected risks. Some articulated understanding the uncertainties of clinical trials, steadfast support and willingness to participate in the future; others reported greater risks than they deemed acceptable and unlikelihood of volunteering again. A few indicated mistrust of trial sponsors and ethics. Participants’ most profound criticism was not about unexpected results, but perceived delays in unblinding and gaps in post-trial dissemination of information. Future HIV vaccine trials may benefit from increased emphasis on: (1) communication mechanisms among participants, investigators and trial sponsors, and (2) post-trial dissemination of information and psychosocial support.