Hepatitis A: a serological study in the Canadian Armed Forces.

Sera were collected from 3958 Canadian Forces personnel, including recruits, personnel posted to bases in Canada and on rotation with United Nations Peacekeeping forces, and the crew of a Canadian destroyer. All sera were tested for the presence of anti-hepatitis A antibodies by a competitive radioimmunoassay. The overall prevalence of anti-hepatitis A antibodies was found to be 23.5% (3.2% to 40.0%). The incidence of viral hepatitis A, as measured by seroconversion in paired sera, was found to be 0.17% (0.01% to 1.42%). The study results support the existence of a direct relationship between increasing age and an increased prevalence of anti-hepatitis A antibodies.