Disclosing of participation in an HIV vaccine trial in southwestern Uganda - the effect on participant engagement

Developing a safe, effective HIV vaccine remains important for the control of the epidemic. However, the development and testing of such a vaccine faces a range of social and behavioural challenges including potential stigmatisation, leading to non-disclosure of trial participation. We explored disclosure of participation in an HIV PrEP and vaccine trial to understand its effect on participant engagement. Between 22 September 2021 and 8 August 2023, 5% (30) of individuals in an HIV vaccine trial (PrEPVacc trial [NCT04066881]) were purposively selected for repeat in-depth interviews at 2, 6 and 12 months of participation in the trial. Forty-five other individuals took part in six focus group discussions, divided equally by gender, with each group comprising 6 to 10 participants. Experiences with vaccination, motivation to participate, and disclosure of participation were explored. Data were analysed thematically using a manual framework analysis approach. Disclosure was reported to enhance participation. Participants disclosed to friends, sexual partners, family members, and employers. Reasons for disclosure included a desire to participate openly and comfortably, to gain others support including financial and physical, and to motivate others. Men and younger participants disclosed more readily than women and older participants. Concerns like fear of being suspected of infidelity or having HIV, blame, and relationship breakages hampered disclosure. A lack of confidence in explaining what the study was about prevented disclosure, as a failure to explain attracted negative reactions including disapproval. As participants gained confidence in the study, approval and support from others improved. Participants who disclosed their participation tended to adhere to study requirements better and encountered less discomfort about taking part, or fear of potential social harm. Successful HIV vaccine trial participation calls for proactive public engagement and awareness campaigns. Disclosure by study participants to significant others about taking part could increase participation, strengthen retention and adherence.