title: Willingness to participate in HIV vaccine trials: the impact of trial attributes.
abstract: OBJECTIVE
  To assess willingness to participate (WTP) in hypothetical Phase III preventive HIV vaccine trials, and the impact of trial attributes on WTP, among low socioeconomic, ethnically diverse adults from communities at elevated risk for HIV infection.
  
  
  METHODS
  Participants (n=123; median age=38; 69% male; 37% Latino; 14% African-American) were recruited in Los Angeles in 2003 using multi-site, venue-based sampling. WTP was assessed for eight hypothetical HIV vaccine trials that varied across seven dichotomous attributes, using a 2(7-4) fractional factorial experimental design. Individual-specific impact of vaccine trial attributes on WTP was estimated using within-individual ANOVA and then meta-analyzed across individuals.
  
  
  RESULTS
  Mean WTP for eight hypothetical vaccine trials ranged from 1.74 to 3.81 (1=highly unlikely, 5=highly likely). Lower WTP was associated with vaccine-induced infection risk (impact=0.88, p<0.0001), false HIV-positives (0.53, p<0.0001), no provision of free HIV medications (0.52, p<0.0001), and longer trial duration (0.27; p=0.0002).
  
  
  CONCLUSIONS
  HIV vaccine trial attributes may strongly influence WTP. Although existing candidate vaccines cannot cause HIV infection, perceptions of risk may impede WTP. Eliciting trial preferences and concerns prior to trial implementation may enable accommodation of participant preferences and support tailored interventions to address concerns and misconceptions to facilitate enrollment in safe and ethical trials among vulnerable communities.
authors.affiliation: University of Toronto, Faculty of Social Work, Centre for Applied Social Research, Toronto, Ontario, Canada. p.newman@utoronto.ca
authors.forename: Peter A
authors.initials: PA
authors.lastname: Newman
authors.forename: Naihua
authors.initials: N
authors.lastname: Duan
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Ellen
authors.initials: E
authors.lastname: Rudy
authors.forename: Danielle
authors.initials: D
authors.lastname: Seiden
authors.forename: Lisa
authors.initials: L
authors.lastname: Kakinami
authors.forename: William
authors.initials: W
authors.lastname: Cunningham
mesh_terms: D016915:AIDS Vaccines / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000193:education / Q000523:psychology; D000704:Analysis of Variance; D002755:Choice Behavior; D017326:Clinical Trials, Phase III as Topic / Q000379:methods / Q000523:psychology*; D005163:Factor Analysis, Statistical; D005260:Female; D015658:HIV Infections / Q000517:prevention & control / Q000523:psychology*; D006301:Health Services Needs and Demand; D006630:Hispanic or Latino / Q000193:education / Q000523:psychology; D006801:Humans; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000523:psychology*; D012051:Reimbursement Mechanisms; D012107:Research Design; D012959:Socioeconomic Factors; D013997:Time Factors
chemical_list: D016915:AIDS Vaccines