Contextual Drivers of HIV Vulnerability and Retention in Care in the Central African Republic: An Ecological Analysis.

HIV transmission is shaped by specific contextual factors that are best understood through ecological and geospatial analysis. This study aimed to investigate three key drivers of HIV infection and vulnerability in the Central African Republic (CAR), a country affected by a long-standing socio-political crisis. To do so, we used sentinel surveillance data from antenatal HIV screening between 2019 and 2021 to estimate the spatial distribution of HIV and conducted an ecological analysis to examine its association with (1) forced population displacement and the presence of internally displaced persons (IDPs), (2) the location of small-scale artisanal mining sites, and (3) retention in care among people living with HIV receiving antiretroviral therapy (ART). As a result, we estimated national HIV prevalence was 2.0%, with clearly defined areas with high prevalence (rates exceeding 5%). Significant regional differences were observed in loss to follow-up (LTFU) rates and care retention dynamics. A notable geographic overlap was found between regions with higher prevalence of HIV, areas of forced displacement, and zones with informal mining activities. These findings, in line with previous studies, suggest a strong interaction between displacement, high-risk behaviours associated with mining and mobility, poor retention in care, and increased HIV vulnerability-particularly among young women. This study underpins the idea that vulnerability to HIV or failure to access to ART is mostly due to surrounding contextual factors beyond the individual-level control. They underscore the need for context-specific interventions such as differentiated service delivery models, mobile clinics, and targeted programs focused on identified areas with higher HIV prevalence and vulnerable groups, including displaced populations, miners, and women. In conclusion, our results highlight the complex challenges of HIV prevention and care in fragile and conflict-affected settings.