Men who have sex with men may now be at considerably higher risk of acquiring HIV than other at-risk groups such as female sex workers or young people of either sex, if findings by the International AIDS Vaccine Initiative (IAVI) of HIV incidence at two centres in Kenya can be generalised to other populations. The study, which compared the Kenyan populations with a largely heterosexual group from South Africa, also found lower-than-expected HIV incidence amongst female sex workers and their clients. The researchers also found that recruiting MSM into the study was easier than expected, but note that there was a particularly high dropout rate in MSM.