Background: Hepatitis B is an important public health concern in South Africa (SA). The hepatitis B virus (HBV) vaccine was introduced into the South African Expanded Programme on Immunisation (EPI-SA) in 1995. There is no 'catch-up' programme in place. The duration of protection after hepatitis B vaccination in the SA population is unknown. Waning of vaccine-induced immunity leaves people at risk of acquiring hepatitis B infection in settings where the prevalence of infection is high and horizontal transmission is likely.
Objective: To assess immunity to HBV in patients at presentation to a paediatric haematology and oncology unit.
Methods: An audit of hepatitis profiles was done of all new patients seen in the unit from January 2012 to December 2013. Patients were classified as immune (antibody levels to hepatitis B surface antigen (anti-HBs) >100 mIU/ml), low immune (anti-HBs 10 - 100 mIU/ml) and not immune (anti-HBs <10 mIU/ml).
Results: Of the 210 patients included (median age 6.5 years), 84 (40.0%) had no immunity to hepatitis B despite presumed vaccination as part of the EPI schedule. Six patients tested positive for hepatitis B core antibody (anti-HBc), consistent with previous infection. No patients had active hepatitis B infection (hepatitis B surface antigen-positive). Most human immunodeficiency virus (HIV)-infected patients were not immune to HBV (80.0%).
Conclusion: A significant number of children in SA are not immune to hepatitis B despite vaccination being part of the EPI-SA. Combined passive-active immunisation should be considered for all oncology patients in settings where exposure to HBV is possible. Consideration should also be given to offering booster vaccination to the population as a whole.