Hepatitis A vaccines.

The global disease burden associated with hepatitis A virus (HAV) is expected to increase in the coming years due to a shift in the epidemiological pattern of the disease. A decrease in the prevalence of natural immunity is leading to an increased number of adolescents and adults susceptible to a disease that is associated with greater morbidity, mortality and treatment costs in older-age groups. Current HAV vaccines have been shown to be safe, highly immunogenic and confer long-lasting protection against HAV disease. Vaccine-induced antibodies persist for more than 12 years in vaccinated adults and mathematical modeling predicts antibody persistence for more than 25 years in over 95% of vaccine recipients. However, the cost of HAV vaccines has been prohibitive for some countries. Recent studies in countries with transitioning HAV endemicity indicate that the cost-benefit ratio of mass vaccination against HAV would be similar to other routine childhood vaccinations.