Purpose of review
A relatively neglected topic to date has been the occurrence of concentrated epidemics within generalized epidemic settings and the potential role of targeted interventions in such settings. We review recent studies in high-risk groups as well as findings relating to geographical heterogeneity and the potential for targeting ‘high-transmission zones’ in the ten highest HIV prevalence countries in sub-Saharan Africa and the world.
Recent findings
Recent studies have confirmed earlier findings that, even in the context of generalized epidemics, men who have sex with men (MSM) have a substantially higher prevalence than the general population. Estimates of prevalence of HIV among people who inject drugs (PWID) in sub-Saharan countries are rarely available and, when they are, often outdated. We identified recent studies of sex workers (SW) in Kenya and Uganda. In all three cases – MSM, PWID and SW – HIV prevalence estimates are mostly based on convenience. Moreover, good estimates of the total size of these populations are not available. Our review of recent studies of high-risk populations defined on the basis of geography showed very high levels of both new and existing infections in Kenya (slums), South Africa (peri-urban communities) and Uganda (fishing villages).
Summary
Recent empirical findings combined with evidence from phylogenetic studies and supported by mathematical models provide a clear rationale for testing the feasibility, acceptability, and effectiveness of targeted HIV prevention approaches in hyper-endemic populations to supplement measures aimed at the general population.