Hepatitis A seroprevalence in homosexual and heterosexual men.

OBJECTIVE To determine the seroprevalence of hepatitis A antibodies in homosexual and heterosexual males attending a genitourinary medicine (GUM) clinic. DESIGN Prospective study of male patients recruited from a GUM clinic during a 10 week period in 1993. SETTING Central London outpatient GUM department at Chelsea and Westminster Hospital. SUBJECTS 255 patients were recruited, comprising 185 homosexual and 70 heterosexual males. Ninety two men were known to be HIV-positive, of whom 89 were homosexual. MAIN OUTCOME MEASURES Serum samples were screened for both IgM and IgG antibodies to hepatitis A by enzyme linked immunoassay. Results were matched to an anonymously completed questionnaire. RESULTS 81 of the 255 subjects (31.8%) had been exposed to hepatitis A, two of whom were IgM positive. There were similar hepatitis A seroprevalence rates in homosexual (32.4%) and heterosexual men (30.0%). Although 48.1% of the homosexual men were known to be HIV-positive, compared with 4.3% of the heterosexuals. Hepatitis A seroprevalence remained comparable in both groups after patients with known HIV infection were excluded from the analysis. 11.4% of the heterosexual men admitted to oral-anal sexual contact compared with 62.2% of the homosexual men. This sexual practice was not associated with antibodies or a past history of hepatitis A exposure. CONCLUSIONS There was no detectable difference in hepatitis A seroprevalence between male homosexual and heterosexual GUM clinic attenders, despite a much higher level of oral-anal sexual activity among the homosexual population.