Role of sexual and non-sexual practices in the transmission of hepatitis B.

Medical, social, and sexual histories were taken from 198 men attending a department for sexually transmitted diseases. Their blood was tested for hepatitis B surface antigen and its antibody, and also for syphilis and liver function. Infection with hepatitis B virus was found to be common among practising homosexuals and to occur much more frequently in them than in heterosexuals. Hepatitis B appeared to be transmitted sexually rather than by other means, but it was not possible in this study to link its transmission with any particular homosexual practice. However, risk of infection increased considerably with the number of sexual partners and nearly half of those with more than 40 sexual partners had been infected.