Willingness of volunteers in an HIV incidence cohort to participate in a future HIV vaccine trial in Kisumu County, Kenya

Future efficacy testing of candidate vaccines and other interventions to prevent HIV will require engagement of vulnerable populations. Here, we assessed willingness to participate in future clinical trials among participants recruited for an HIV incidence study in western Kenya. From February 2017 to May 2018, we recruited people living without HIV who reported multiple sexual partners into a 24-month HIV incidence cohort study in Kisumu County, Kenya. At screening for study eligibility and study exit, participants completed comprehensive sociobehavioral questionnaires. They were also provided a general definition of a clinical trial and asked if they would be willing to participate in a future clinical trial of a candidate HIV vaccine. At enrollment, participants were also asked about facilitators and barriers to participation in such a clinical trial. Among 940 individuals screened for enrollment into the HIV incidence study, 919 (97.8%) reported willingness to participate in a future clinical trial of a candidate HIV vaccine. Willing individuals were more likely than unwilling ones to have exchanged sex for goods or money (60.1% vs. 35.0%, p = 0.0237) and were less likely to believe that an individual’s HIV status can be inferred by looking at them (8.7% vs. 23.8%, p = 0.0175). Willingness to participate was similarly common among participants who enrolled (608/618, 98.4%) and completed the study (518/533, 97.2%). The vast majority of the 618 enrolled participants reported obtaining HIV research information from radio/TV (n = 608, 98.1%) and newspapers/magazines/brochures (n = 579, 93.1%). Advantages they identified included HIV education (n = 594, 95.8%), access to healthcare (n = 576, 93.2%), and HIV counseling/testing (n = 574, 92.9%). Among 271 female participants, 235 (86.7%) identified free pregnancy testing as an advantage while 28 (19.4%) were unlikely to participate in a study that required the use of contraception. Among 10 enrollees who were unwilling to participate, five (50%) cited a fear of acquiring HIV and five (50%) cited fear of vaccine adverse effects. We identified a highly willing population for future testing of HIV preventive vaccines. Specific barriers to participation should be addressed in recruitment efforts.