Hepatitis B virus infection and vaccination status of high risk people in Sydney: 1982 and 1991

OBJECTIVES: To determine the change in prevalence of hepatitis B virus infection among "at risk" patients attending the Sydney Sexual Health Centre between 1982 and 1991 and to determine the hepatitis B vaccination status of the 1991 group. STUDY POPULATION: Consecutive patients attending the Centre between 1 July and 31 December 1991 who belonged to at least one of the following risk groups: men who have sex with men (n = 351); female prostitutes (n = 124); and injecting drug users (n = 153). DESIGN: Hepatitis B infection status was assessed on the basis of patient history and blood testing. All patients without a history of hepatitis B infection or vaccination were offered screening for serum markers of hepatitis B infection. Hepatitis B infection status was correlated with age, sex, country of birth, sexual behaviour and injecting drug use and was analysed separately according to risk category. RESULTS: The prevalences of any hepatitis B marker were: men who have sex with men 38.2% (61.0% in 1982; P < 0.0001); local female prostitutes 14.1% (28.8% in 1982; P = 0.024); international female prostitutes 58.4%; and injecting drug users 42.0%. Of those in the 1991 sample without a history of hepatitis B infection, 27.6% of men who have sex with men, 27.9% of local female prostitutes, 18.2% of international female prostitutes and 7.1% of injecting drug users were vaccinated. CONCLUSIONS: The significantly lower prevalences of serum markers of hepatitis B infection among men who have sex with men and local female prostitutes when compared with 1982 suggest widespread adoption of safer sexual practices. The high prevalence of chronic hepatitis B infection among international female prostitutes indicates a potentially significant source of sexually transmitted hepatitis B infection in Sydney. The low vaccination rates provide an argument for mass vaccination against hepatitis B.