Childhood infection with hepatitis A and B viruses in England and Wales.

Infection with hepatitis B and A viruses during childhood was studied using serum specimens collected from children aged 13 and 14 years by 12 public health laboratories in England and Wales from 1986 to 1995. Six of the 2025 specimens tested for markers of hepatitis B infection showed evidence of earlier resolved infection, one specimen showed evidence of recent infection, and hepatitis B surface antigen (HBsAg) was detected in three specimens. The HBsAg carriage rate of 0.15% (3/2025) was consistent with that expected from vertical transmission before the introduction of antenatal screening and neonatal hepatitis B vaccination, for which the children in our study would not have been eligible. Five of the six children with earlier resolved hepatitis B infection also showed evidence of hepatitis A infection, whose coexistence raises the possibility that both infections were acquired abroad in areas of high endemicity. At present, by adolescence, about one in 200 children has at some time been infected with hepatitis B virus. The current practice of screening pregnant women for HBsAg and selectively vaccinating neonates at high risk of acquiring hepatitis B infection may reduce this rate in the future. Immunisation of all infants against hepatitis B would prevent very few more childhood infections than the current policy. The incidence of hepatitis A infection has fallen in the past decade, suggesting the potential for an epidemic resurgence in the future as more of the population becomes susceptible. The average annual incidence of hepatitis A infection in children aged 0 to 14 years from 1986 to 1995 was 800 per 100 000, fifty times higher than the reported incidence of laboratory confirmed disease in this age group. Most hepatitis A infections in this age group are therefore likely to be subclinical or very mild.