Hepatitis A

Abstract

Hepatitis A virus (HAV) is a single-stranded “nonenveloped” RNA virus in the picornaviridae family. HAV is most often transmitted by the fecal-oral route, but also by contaminated food, water, sexual contact, and intravenous drug use. HAV causes little if any symptoms in the very young. Disease symptoms from liver damage become more frequent in older ages and even fulminant liver failure with death is observed in the elderly. Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease. With lack of sanitation and hygiene, HAV infection occurs early in life inducing life-long protection, whereas in countries with good sanitation and hygiene, infections are seen later in life and are more severe. There is no causal treatment, but available vaccines are well tolerated, have an excellent safety profile and are highly effective with long-lasting protection after 2 doses. Hepatitis A vaccines can be used for pre- as well as for post-exposure prophylaxis and for individual as well as for population protection. Vaccinating a small fraction of the population (3%) – i.e., children aged 1–4 years serving as the reservoir and source of HAV – resulted in herd protection with 96% disease reduction in the whole population of Israel.