Hepatitis B Immunization in a Low-incidence Province of Canada

Abstract

This study provides a comparative cost-effectiveness analysis of three universal im munization programs for hepatitis B virus (HBV). Using three theoretical cohorts of infants, 10-year-olds, and 12-year-olds, a universal immunization program was com pared with a prenatal screening/newborn immunization program involving testing of prepartum women and immunization of newborns of HBsAg-positive mothers. A Mar kov long-term outcome model used Manitoba data to estimate costs and health out comes across the lifespan. The model was based on an HBV incidence rate of 19/ 100,000 and a discount rate of 5% and incorporated the most recent treatment ad vances (interferon therapy). Cost-effectiveness was calculated as the ratio of dollars spent per year of life saved, with costs determined from the perspective of a third- party payer. The universal infant-immunization program, although not cost-saving, was associated with a low, economically attractive cost-effectiveness ratio of $15,900 (Ca nadian) per year of life saved, a figure substantially lower than the ratios of $97,600 and $184,800 (Canadian) associated with the universal programs for 10- and 12-year- olds, respectively. Cost-effectiveness ratios were found to be sensitive to changes in immunization costs, HBV incidence rates, and the rate at which protective antibody levels are lost over time: If these variables move in the directions suggested by current trends, the authors anticipate an increasing economic appeal of universal programs well into the future. A universal program of HBV immunization for infants appears to be economically practical in regions where HBV infection rates are low and stable. Key words: hepatitis B; cost-effectiveness; immunization. (Med Decis Making 1997; 17:472-482)