title: Expectation of volunteers towards the vaccine efficacy of the prime-boost HIV vaccine phase III trial during unblinding.
abstract: A Phase III community-based HIV vaccine trial using the ALVAC-HIV and AIDSVAX B/E prime-boost regimen (RV144) showed a modest vaccine efficacy of 31.2% against HIV acquisition. Participant's understanding of the trial is a key element of its success. This study aimed to understand participant's expectation and response to the overall results of the trial as well after unblinding. Using an open-ended questionnaire, data were collected from 400 participants who came for the unblinding visit. Fifty-three percent received the vaccine and 47% were placebo recipients. The median age was 30 years (range: 22-37). The observed vaccine efficacy of 31.2% was lower than expected by 67.75% of participants compared to higher than expected (by 6%), as expected (by 11.25%), and those with no expectation (15%). A majority of participants (71.5%) were happy and proud, and indicated that it was a good result. The rest were sad or disappointed (22.75%) or acquiescent (5.75%). After unblinding, 67.92% of the vaccine recipients had a positive response and 32.08% were acquiescent. Among placebo recipients, 85.11% were acquiescent and 10.11% indicated that being assigned to the vaccine group would have been better even though vaccine efficacy was only 31.2%. Despite the modest vaccine efficacy, a majority of study participants acknowledged the value of the trial and hoped that information from RV144 could be used for future vaccine development.
authors.affiliation: 1 Vaccine Trial Center, Faculty of Tropical Medicine, Mahidol University , Ratchathewi, Bangkok, Thailand .
authors.forename: Kessuda
authors.initials: K
authors.lastname: Khowsroy
authors.forename: Jittima
authors.initials: J
authors.lastname: Dhitavat
authors.forename: Yupa
authors.initials: Y
authors.lastname: Sabmee
authors.forename: Pataramon
authors.initials: P
authors.lastname: Laowarakul
authors.forename: Jutarat
authors.initials: J
authors.lastname: Wattanakitwichai
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Auetian
authors.forename: Kannika
authors.initials: K
authors.lastname: Lothong
authors.forename: Roongtip
authors.initials: R
authors.lastname: Boondao
authors.forename: Sarawan
authors.initials: S
authors.lastname: Maythaarttaphong
authors.forename: Sunee
authors.initials: S
authors.lastname: Yaemwong
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Excler
authors.forename: Supachai
authors.initials: S
authors.lastname: Rerks-Ngarm
authors.forename: Punnee
authors.initials: P
authors.lastname: Pitisuttithum
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D007722:Health Knowledge, Attitudes, Practice; D064368:Healthy Volunteers / Q000523:psychology*; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D016915:AIDS Vaccines