HIV-related public stigma in the era of "Undetectable = Untransmittable": a population-based study in Hong Kong

Background While global efforts are increasingly relying upon biomedical advancements such as antiretroviral therapy and pre-exposure prophylaxis (PrEP) to end the HIV epidemic, HIV-related stigma remains a concern. This study aimed to assess the general public's awareness and perception of "Undetectable = Untransmittable" (U = U) and PrEP, and the patterns of public stigma towards people living with HIV (PLWH) and their determinants in an Asian Pacific city.Methods A population-based, self-administrated online survey was conducted between 10-20 March 2023. All adults aged >= 18 years and currently living in Hong Kong were eligible. Participants' socio-demographic characteristics, awareness and perception of U = U and PrEP, as well as HIV-related stigma drivers, experience and practices were collected. Latent class analysis was used to delineate population subgroups based on their stigma profiles as reflected by 1.) fear of infection, 2.) concern about socioeconomic ramification of the disease, 3.) social norm enforcement, 4.) perceived stigma in the community, and 5.) stigmatising behaviours and discriminatory attitudes. Memberships of identified subgroups were then correlated with sociodemographic factors, awareness and perception of U = U and PrEP, using multinominal logistic regression.Results Responses from a total of 3070 participants (55% male; 79% aged 18-54) were analysed. A majority, 69% and 81%, indicated that they had never heard of U = U and PrEP respectively, and only 39-40% of participants perceived these to be effective in protection from HIV. Four distinct subgroups were identified, namely "Low stigma" (37%), "Modest stigma" (24%), "Moderate stigma" (24%), and "High stigma" (15%). Compared with "Low stigma", lack of awareness of and/or negative perceptions towards U = U and/or PrEP, not knowing any PLWH were associated with increased odds of higher stigma group membership. Lower educational level and not in employment were associated with increased odds of membership in "Moderate stigma" and "High stigma". While older people were more likely to belong to "High stigma", female were more likely to belong to "Moderate stigma". "Modest stigma" included more younger people who were economically active.Conclusion Two-thirds of participants endorsed modest-to-high HIV-related stigma, suggesting the prevalence of HIV-related stigma was high among the general population in Hong Kong. Tailored interventions targeting specific stigma drivers and manifestations of individuals as reflected from the stigma profiles of distinct subgroups could form an important strategy for stigma reduction.