Hepatitis A: Vaccine Preventable Diseases Surveillance Standards

Overview

The hepatitis A virus (HAV) is transmitted primarily via the faecal/oral route either through ingestion of contaminated food and water or through direct contact with an infectious person. The incubation period is usually 14–28 days, but can be up to 50 days (1). Young children usually have asymptomatic infection, but older children and adults commonly experience symptomatic disease.

The clinical manifestations of acute HAV infection are malaise, fatigue, anorexia, vomiting, abdominal discomfort, diarrhea and jaundice, and are indistinguishable from acute hepatitis caused by other viruses. HAV resolves completely in the vast majority of cases but relapses can occur. Rarely, acute liver failure occurs. The estimated case fatality ratio varies with age from 0.1% among children < 15 years of age, to 0.3% among persons 15–39 years of age, to 2.1% among adults aged ≥ 40 years of age. In contrast to hepatitis B and C, HAV does not cause chronic liver disease.