The epidemiology and control of hepatitis A.

Hepatitis A virus (HAV) infection is endemic in developing countries and remains a public health problem elsewhere. A total of 7430 cases was notified in England and Wales in 1991. Children and young adults were most frequently affected. Risk factors include travel to countries of high endemicity, contact with an infected person and shellfish consumption. Person-to-person spread is common within families, closely knit communities and schools (especially nurseries). The provision of safe water and sanitary disposal of faeces are prerequisites for control of HAV throughout the world. In developed countries, human normal immunoglobulin (HNIG) is used for post-exposure prophylaxis and is given to those travelling abroad prior to possible exposure. Recommendations for the use of hepatitis A vaccine have have recently been made but it is expensive. Further studies on risk factors for infection, and on the efficacy of hepatitis A vaccine in outbreak control, are needed.