Attempting to explain heterogeneous HIV epidemics in sub-Saharan Africa: potential role of historical changes in risk behaviour and male circumcision

摘要: Background A key conclusion of the Four Cities Study, carried out to explore reasons for heterogeneity in HIV epidemic between two cities sub-Saharan Africa with relatively low prevalence (Cotonou and Yaounde) high (Kisumu Ndola), was that differences biological cofactors outweighed sexual risk behaviours. The authors an alternative hypothesis, behaviours were historically higher high-prevalence cities. They also investigate effects different male circumcision on epidemics four Methods transmission model fitted data from Study. Default scenarios included cofactor transmission. Counter-factual simulated without cofactors, historical behaviours, various rates circumcision. Results Simulated adult 1997 default 3.1%, 7.8%, 28.9% 27.1% Cotonou, Yaounde, Kisumu Ndola, respectively, line data. Without even implausibly levels behaviour East could not reproduce observed late 1990s. Increasing proportion men circumcised Ndola 10% 100% reduced 7%. Decreasing Yaounde increased 26%. Conclusions Differences are likely have played a role heterogeneous spread across Africa. effect interventions can vary depending setting, larger more generalised epidemics.