Hepatitis A is an acute viral disease that has been documented since Greek and Roman times. Despite widespread improvement in human waste management and great success of immunization campaigns with the killed hepatitis A vaccine, hepatitis A is still a significant cause of morbidity and even mortality and therefore remains a hot topic for virologists.

An estimated 1.4 million people still contract the disease globally each year, but epidemiological patterns vary considerably depending on geographical location. In developing countries, poor sanitation is behind the frequent occurrence of hepatitis A in nearly all young children. Infections are mostly asymptomatic and create high herd immunity in the population. On the other hand, in developed countries, high hygiene and health-care standards have resulted in a sharp decline in hepatitis A virus (HAV) infection rates and consequent loss of immunity in the general population. This has set the scene for infection to occur at increased rates in adults, who are more likely to suffer from severe liver disease.  For developed countries, international travelers and immigrants from HAV endemic regions are a potential source of infections, justifying the phrase “hepatitis A is traveling to us.”

This monograph reviews recent insights into HAV virology, epidemiology, clinical features, and the latest evidence on vaccination against hepatitis A.

by Francesco Negro