High prevalence of occult hepatitis B among immigrant students in Canada: A case for universal immunization of young adults.

The prevalence and demographic characteristics of positive hepatitis B (HBV) serology were determined among post secondary health care students in Ottawa. Ontario. HBV seropositivity was defined as the presence of HBV surface antigen (HBsAg) or antibodies to HBV core or surface antigens by radioimmunoassay. HBsAg-positive students were advised to visit their family doctors; the health measures that resulted were observed. Among 600 students born in North America, the proportion of HBV seropositive and HBsAg-positive were 0.8 and 0.2%, respectively. Among the 63 students born outside Europe or North America. 22.2% were HBV seropositive (odds ratio 29.7. confidence interval 10.1 to 97.5) and 7.9% were HBsAg-positive (odds ratio 54.2, confidence interval 5.9 to 2568.3). Of the seven HBsAg-positive students, none had known their HBV status - five visited their doctors, two of whom sought and immunized susceptible household contacts. This survey supports the view that many sexually active young adults integrating into Canadian society from immigrant families are unknowingly HBsAg-positive, and when their HBV status is identified to them and their doctors, appropriate measures for the protection of close contacts are often overlooked. Physician education about the management of HBV carriers should be improved and consideration given to the universal HBV immunization of young adults.