Hepatitis A virus antibodies in Australian blood donors: Implications for immunoglobulin sufficiency

Background Passive immunisation is an important means of preventing hepatitis A in the most vulnerable populations in the event they are exposed. Trends in hepatitis A seroprevalence may impact on the production of effective immunoglobulin products for passive immunisation. Methods The seroprevalence of hepatitis A antibodies in blood donors in capital cities around Australia was measured using a commercial ELISA. Hepatitis A antibodies were quantified using the same commercial kit in a random sample of those who were seropositive. Results An estimated 51% (95% CI 48–54%) of Australian blood donors were seropositive for hepatitis A. Rates varied across the country and increased with age. The geometric mean titre (GMT) of those who were seropositive among our sample was 1246.8 mIU/mL (geometric standard deviation 11.8 mIU/mL) and increased with age. Conclusion Comparison with published data supported an increase in seroprevalence in younger age groups. The seeming increase in seroprevalence among donors is encouraging regarding Australia's ability to maintain immunoglobulin sufficiency. However, the overall GMT of hepatitis A antibodies in donations may be prone to decrease as current donor cohorts age.