Who should receive hepatitis A vaccine? Considerations for the development of an immunization strategy.

The availability of efficacious hepatitis A vaccines should greatly facilitate the prevention of hepatitis A virus (HAV) infection. Groups at high risk of HAV infection have been identified from epidemiological studies and include both children and adults. While certain high-risk adults, such as travellers, could be a convenient target for vaccination, selective immunization of high-risk adults would not be expected to lower the overall rates of infection in most countries. Because a significant proportion of HAV infections occur in children, the eventual objective should be the integration of hepatitis A vaccine into routine childhood immunization schedules. This would reduce disease incidence by preventing infections in children and by preventing infections in adults that are acquired from children. The cyclical patterns of hepatitis A observed in many countries are related to levels of immunity in the population. The elimination of the susceptibility of a population to HAV infection through immunization could eliminate this well known human disease. This suggests that eradication of HAV infection should be attainable with effective hepatitis A vaccines.