Correspondence to. METHODS: A questionnaire was given to female sex workers in order to obtain information about demographic, socioeconomic and behavioral variables.
A high spatial mobility was observed, with Complete absence of previous vaccine against hepatitis B was referred by Overall, the presence of any hepatitis B marker was observed in participants prevalence of The first evidence that hepatitis B can be transmitted by the sex route dates back to the early seventies, with the virus being isolated from saliva, semen 1 and vaginal secretions 2 , and being frequently detected in patients seen at clinics of sexually transmitted diseases 3.
The hypothesis of sexual transmission eventually gained support from investigations involving persons with intensive exposure, such as sex workers 4 and male homosexuals 5. However, the marginalization and discrimination which these groups always suffer caused them to receive little attention from investigators in the health area 6. The dissemination of the acquired immunodeficiency syndrome aids , starting in the 's, was a crucial fact for sex workers SW to start to be investigated more frequently.
Because of the similarity of the mechanisms of transmission and, consequently, of the more vulnerable groups, research on aids indirectly provided information about behavioral and biological aspects related to the transmission of hepatitis B. Although the human immunodeficiency virus HIV has a much lower infectivity than the hepatitis B virus HBV 7 , it is undeniable that its impact on public opinion and on the academic community is considerably more intense.
Because of this, investigations involving SW are directed at aids much more than at hepatitis, impairing the knowledge of the epidemiologic situation of the latter in this high-risk population group. This clearly occurs in Brazil, where information about hepatitis among SWs is quite scarce. These places were visited by the investigating team, which included a social assistant with extensive experience in work with city SW and a public health physician.
