Determinants of HIV serconversion in an era of increasing HIV infection among young gay and bisexual men.

Men were followed prospectively to identify demographic and behavioural characteristics associated with HIV seroconversion. Thirty-six HIV cases were identified (HIV incidence 1.9/100 person-years). Unprotected receptive anal sex with HIV-positive partners and with casual partners regardless of serostatus was associated with seroconversion. Having ever been in prison or in a psychiatric ward were predictive of seroconversion. HIV prevention efforts should address issues related to mental and social stability and serodiscordant relationships to reduce the risk of seroconversion.