Kessuda KhowsroyJittima DhitavatYupa SabmeePataramon LaowarakulJutarat WattanakitwichaiJiraporn AuetianKannika LothongRoongtip BoondaoSarawan MaythaarttaphongSunee YaemwongJean Louis ExclerSupachai Rerks-NgarmPunnee PitisuttithumMahidol UniversityUS Military HIV Research ProgramThailand Ministry of Public Health2018-11-092018-11-092014-01-01AIDS Research and Human Retroviruses. Vol.30, No.11 (2014), 1041-104519318405088922292-s2.0-84931351656https://repository.li.mahidol.ac.th/handle/123456789/34055© 2014 Mary Ann Liebert, Inc. 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.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.1089/aid.2013.0136