The Impact of the Hepatitis B Virus Vaccine on the Incidence of Hepatitis B Virus–Associated Membranous Nephropathy

Abstract

Background The hepatitis B virus (HBV) vaccine has resulted in a decline in the incidence of HBV carriage and hepatocellular carcinoma in southeast Asia. Vaccine efficacy in Africa has not been adequately assessed. Objective To report on the impact of HBV vaccination in South Africa on HBV-associated membranous nephropathy (MN) over 6 years. Methods King Edward VIII Hospital in Durban is the only tertiary referral center for the province of KwaZulu-Natal for children with renal diseases. The HBV vaccine was introduced into the South African Expanded Programme on Immunisation on April 1, 1995; vaccine coverage rates between April 1, 1995, and December 31, 2001, for children for the first, second, and third doses were 85.4%, 78.2%, and 62.0%, respectively. Hepatitis B virus status was determined using a radioimmunoassay (January 1, 1984–March 31, 1991) or an enzyme-linked immunosorbent assay. Membranous nephropathy was confirmed by the results of a renal biopsy. The hospital average annual incidence of HBV-associated MN was compared before and after vaccination and according to age groups. Results Between January 31, 1984, and December 31, 2001, there were 119 children with HBV-associated MN; their mean age was 7 years (range, 1-14 years), and 101 (84.9%) were males. The average annual rate ratio per 10⁵ child population was 0.25. The overall incidence rate ratio showed a significant decrease from January 1, 2000, to December 31, 2001, compared with the preimmunization period (January 1, 1984–December 31, 1994) (incidence rate ratio, 0.12; 95% confidence interval, 0.03-0.50). Children from birth to the age of 4 years experienced no disease after 1998. Children aged 5 to 10 years showed a significant decrease in 2000-2001 compared with the prevaccination years (incidence rate ratio, 0.19; 95% confidence interval, 0.05-0.80). Conclusion The HBV vaccine, even at low coverage for the full South African Expanded Programme on Immunisation schedule, reduced the hospital incidence of HBV-associated MN over 6 years.