Exploring evidence for behavioral risk compensation among participants in an HIV vaccine clinical trial

Julia E. Painter, Ralph J. DiClemente, Lauren Jimenez, Theron Stuart, Jessica M. Sales, Mark J. Mulligan

Research output: Contribution to journalArticlepeer-review


Background HIV vaccine trial participants may engage in behavioral risk compensation due to a false sense of protection. We conducted an ancillary study of an HIV Vaccine Trials Network (HVTN) vaccine efficacy trial to explore risk compensation among trial participants compared to persons who were willing to participate but ineligible based on previous exposure to the Ad5 virus (Ad5+) across three timepoints. Methods Participants were drawn from the Atlanta, GA site of the HVTN 505 vaccine trial. From 2011–2013, all persons who met prescreening criteria for the clinical trial and presented for Ad5 antibody testing were invited to participate in the ancillary study. Data were collected from vaccine trial participants (n = 51) and Ad5+ participants (n = 60) via online surveys across three timepoints: baseline, T2 (after trial participants received 2/4 injections) and T3 (after trial participants received 4/4 injections). Data analyses assessed demographic, psychosocial, and behavioral differences at baseline and changes at each timepoint. Results At baseline, Ad5+ participants were less likely to have some college education (p = 0.024) or health insurance (p = 0.008), and were more likely to want to participate in the vaccine trial “to feel safer having unprotected sex” (p = 0.005). Among vaccine trial participants, unprotected anal sex with a casual partner (p = 0.05), HIV transmission worry (p = 0.033), and perceived chance of getting HIV (p = 0.027), decreased across timepoints. Conclusions Study findings suggest that persons with previous exposure to Ad5 may be systematically different from their Ad5-negative peers. Unprotected anal sex with a casual partner significantly decreased among HIV vaccine trial participants, as did HIV worry and perceived chance of getting HIV. Findings did not support evidence of risk compensation among HIV vaccine trial participants compared to Ad5+ participants.

Original languageEnglish (US)
Pages (from-to)3558-3563
Number of pages6
Issue number28
StatePublished - Jun 16 2017


  • Ad5+
  • Behavioral disinhibition
  • HIV vaccine
  • HVTN 505
  • Risk compensation
  • Vaccine trial

ASJC Scopus subject areas

  • Molecular Medicine
  • General Immunology and Microbiology
  • General Veterinary
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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