Hepatitis A vaccines
Hepatitis A is an acute, usually self-limiting disease of the liver caused by hepatitis A virus (HAV). HAV is trasmitted from person to person, primarily by the faecal-oral route. The incidence of hepatitis A is closely related to socioeconomic development, and seroepidemiological studies show that prevalence of anti-HAV antibodies in the general population varies from 15% to close to 100% in different parts of the world. An estimated 1.5 million clinical cases of heptatitis A occur each year. In young children HAV infection is usually asymptomatic whereas symptomatic disease occurs more commonly among adults. Infection with HAV induces lifelong immunity. In areas of low endemicity, hepatitis A usually occurs as single cases among persons in high risk groups or as outbreaks involving a small number of persons. In highly endemic areas, most persons are asymptomatically infected with HAV during childhood and clinical hepatitis A is uncommon. In countries of low and intermediate endemicity, adult disease is seen more often and hepatitis A may represent a substantial medical and economic burden.
Currently, 4 inactivated vaccines against HAV are internationally available. All 4 vaccines are safe and effective, with long-lasting protection. None of the vaccines are licensed for childred aged under 1 year.