Serosurveillance of prevalence of undiagnosed HIV-1 infection in homosexual men with acute sexually transmitted infection

The prevalence of HIV-1 infection among homosexual and bisexual men attending genitourinary medicine clinics, measured through anonymised testing of samples taken to test for syphilis, has declined in recent years.1 This decline may be spurious, however, because the proportion of such men who have serum samples taken to test for syphilis has declined and because specialist HIV services have drawn patients infected with HIV away from the genitourinary medicine clinics that participate in seroepidemiological surveillance.2 We therefore studied the prevalence of HIV-1 in homosexual and bisexual men without a diagnosis of HIV-1 infection who presented with a new episode of an acute sexually transmitted infection: this group is likely to attend genitourinary medicine clinics and undergo testing for syphilis.