The HVTN503/Phambili HIV vaccine trial: A comparison of younger and older participants

Jonathan E. Volk, Nancy A. Hessol, Glenda E. Gray, James G. Kublin, Gavin J. Churchyard, Koleka Mlisana, Maphoshane Nchabeleng, Susan P. Buchbinder, Linda Gail Bekker

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


By comparing younger to older participants enrolled in a HIV vaccine efficacy trial, we aimed to gain insights into the inclusion of adolescents in future trials. This was a sub-analysis of a multisite HIV vaccine randomized clinical trial in South Africa, conducted January-September 2007. Motivations for trial enrolment, social harms, adverse events and loss to follow-up were compared between younger (18-20 years old) and older participants (21-35 years old). Both younger (n = 238) and older participants (n = 563) were equally likely to report enrolling for altruistic reasons. Younger females were less likely than older participants to join for trial reimbursement (p = 0.005), while younger males were more likely to enrol because the vaccine may provide protection from HIV-acquisition (p < 0.001). There were no significant differences in the number of social harms reported. Compared to males over 20 years old, 18-20-year-old females were less likely to experience adverse events (OR = 0.1, CI 0.01-0.80) and no more likely to be lost to follow-up (OR = 0.7, CI 0.39-1.25), while 18-20-year-old males were no more likely to experience adverse events (OR = 1.3, CI 0.58-2.83) or loss to follow-up (OR = 0.8, CI 0.51-1.41). Our data support the inclusion of younger participants who are at risk for HIV in future HIV vaccine efficacy trials.

Original languageEnglish
Pages (from-to)332-340
Number of pages9
JournalInternational Journal of STD and AIDS
Issue number5
Publication statusPublished - Apr 2014


  • AIDS
  • HIV
  • South Africa
  • clinical trials
  • prevention
  • vaccination
  • vaccine trials
  • youth


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