Hepatitis A is an acute, usually self-limiting, disease of the liver caused by the hepatitis A virus (HAV). HAV is transmitted from person to person, primarily by the fecal-oral route, and is closely associated with poor sanitary conditions. The most common modes of transmission include close personal contact with an infected person and ingestion of contaminated food and water.
The virus occurs worldwide and causes about 1.5 million cases of clinical hepatitis each year. Humans are the only reservoir of HAV.
Millions of persons have now been vaccinated against HAV. The current vaccines are well tolerated and no serious adverse events have been statistically linked to their use. Contraindications to hepatitis A vaccination include a known allergy to any of the vaccine components. Hepatitis A vaccine may be administered with all other vaccines included in the Expanded Program on Immunization and with vaccines commonly given for travel. None of the vaccines are licensed for children aged < 1 year.
Planning for large-scale immunization programs against hepatitis A should involve careful analyses of cost-benefit and sustainability of different appropriate hepatitis A prevention strategies, as well as an assessment of the possible long-term epidemiological implications of vaccination at different levels of coverage.