What lies in the shadows: The collateral consequences of constructing 'high risk' targets in public health.

This paper traces the social construction of 'high risk' targets in biomedical public health prevention programmes. We ask: what are the intended and unintended effects of such targeted approaches? Who and what do they render visible and invisible? We are particularly interested in exploring the effects of public health targeting strategies on those who remain outside of these targeted approaches. Although targeted public health approaches are designed for economic and epidemiological efficiency, they can widen healthcare disparities, particularly for vulnerable groups who are already socially stigmatized. Through qualitative interviews and focus groups, we comparatively examined how access to HIV pre-exposure prophylaxis (PrEP) is structured in Ireland and Kenya. While public health officials have strong rationales for targeting high-risk groups in both locations, we find that these strategies often create considerable blind spots both in the modes of delivery, with significant collateral effects on who considers themselves part of a targeted group. Invisibility occurs not only directly, through risk stratification, but also indirectly, when clinical and institutional path dependencies, delivery strategies, and health provider targeting combine to prioritize specific populations, creating structural and often long-lasting barriers for those outside predefined risk categories. We highlight how these barriers reinforce inequities in PrEP access, invisibilizing populations who remain at high risk of HIV infection. Our research holds valuable lessons for other areas of public health 'targeting', particularly as public health moves further toward a rhetoric of precision.