Low prevalence of hepatitis B markers among Mexican female sex workers.

OBJECTIVES To estimate the prevalence and associated risk factors of hepatitis B virus (HBV) serological markers in female sex workers (FSW) in Mexico City. METHODS The study population consisted of 1498 FSW who attended a detection centre for human immunodeficiency virus (HIV) in Mexico City, between January and October 1992. Study participants responded to a standardised questionnaire and provided a blood sample for serology of syphilis, HIV, and HBV. RESULTS A total of 0.2% (95% CI 0.1-0.3) of the population were hepatitis B surface antigen (HBsAg) carriers. The general prevalence of antibodies to hepatitis B core antigen (anti-HBc) was 6.3% (95% CI 5.5-7.1). This marker of previous exposition to HBV, was independently associated by logistic regression multivariate analysis with age, working in the street, and history of blood transfusion (BT) before 1987 (OR 4.8, 95% CI 2.1-11.3). Syphilis prevalence was 7.6% (95% CI 6.2-8.9) and HIV prevalence was 0.1% (95% CI 0-0.3). CONCLUSIONS The prevalence of HBV infection in this group of Mexican FSW is lower than previously reported in other countries. In addition, the frequency of HBsAg carriers is similar to that in the general Mexican population. The absence of two major risk factors for HBV transmission in this group of FSW--that is, injecting drug use and anal intercourse, could help to explain this finding. However, the positive association between anti-HBc and history of blood transfusion demonstrated here, highlights the need to reinforce strict control of blood supplies in Mexico.