A social vaccine? Social and structural contexts of HIV vaccine acceptability among most-at-risk populations in Thailand.

A safe and efficacious preventive HIV vaccine would be a tremendous asset for low- and middle-income country (LMIC) settings, which bear the greatest global impact of AIDS. Nevertheless, substantial gaps between clinical trial efficacy and real-world effectiveness of already licensed vaccines demonstrate that availability does not guarantee uptake. In order to advance an implementation science of HIV vaccines centred on LMIC settings, we explored sociocultural and structural contexts of HIV vaccine acceptability among most-at-risk populations in Thailand, the site of the largest HIV vaccine trial ever conducted. Cross-cutting challenges for HIV vaccine uptake - social stigma, discrimination in healthcare settings and out-of-pocket vaccine cost - emerged in addition to population-specific barriers and opportunities. A 'social vaccine' describes broad sociocultural and structural interventions - culturally relevant vaccine promotion galvanised by communitarian norms, mitigating anti-gay, anti-injecting drug user and HIV-related stigma, combating discrimination in healthcare, decriminalising adult sex work and injecting drug use and providing vaccine cost subsidies - that create an enabling environment for HIV vaccine uptake among most-at-risk populations. By approaching culturally relevant social and structural interventions as integral mechanisms to the success of new HIV prevention technologies, biomedical advances may be leveraged in renewed opportunities to promote and optimise combination prevention.