Hepatitis B epidemiology in Latin America.

The available data on prevalence of hepatitis B virus (HBV) infection in Latin America are incomplete and largely based on analysis of blood banks, which are not stratified by age or social class. An epidemiological study was recently undertaken in six countries in Latin America to update the data. The highest seroprevalence of antibody to the HBV core antigen (anti-HBc) was found in the Dominican Republic (21.4%), followed by Brazil (7.9%), Venezuela (3.2%) and Argentina (2.1%). The lowest seroprevalence was found in Mexico (1.4%) and Chile (0.6%). The seroprevalence in different regions of Brazil varied from 21% in Manaus to 1.2% in Fortaleza. There were no differences in seroprevalence of anti-HBc between females and males except in Brazil (significantly higher in males) and in the Dominican Republic (significantly higher in females). In Brazil alone, higher seroprevalence was associated with lower socioeconomic class. In both the Dominican Republic and Brazil, seroprevalence was high in childhood, and in Brazil and Argentina, anti-HBc was detected in 3.0-6.6% of children up to 1 year old, suggesting vertical transmission. Other risk factors included dental and surgical procedures, sexual activity and tattooing. There was an increase in seroprevalence in all countries at or after adolescence, suggesting that sexual activity is a major route of transmission.