title: The impact of assumptions regarding vaccine-induced immunity on the public health and cost-effectiveness of hepatitis A vaccination: Is one dose sufficient?
abstract: Hepatitis A vaccination stimulates memory cells to produce an anamnestic response. In this study, we used a mathematical model to examine how long-term immune memory might convey additional protection against clinical/icteric infections. Dynamic and decision models were used to estimate the expected number of cases, and the costs and quality-adjusted life-years (QALYs), respectively. Several scenarios were explored by assuming: (1) varying duration of vaccine-induced immune memory, (2) and/or varying levels of vaccine-induced immune memory protection (IMP), (3) and/or varying levels of infectiousness in vaccinated individuals with IMP. The base case analysis assumed a time horizon of 25 y (2012 - 2036), with additional analyses over 50 and 75 y. The analyses were conducted in the Mexican public health system perspective. In the base case that assumed no vaccine-induced IMP, the 2-dose hepatitis A vaccination strategy was cost-effective compared with the 1-dose strategy over the 3 time horizons. However, it was not cost-effective if we assumed additional IMP durations of at least 10 y in the 25-y horizon. In the 50- and 75-y horizons, the 2-dose strategy was always cost-effective, except when 100% reduction in the probability of icteric Infections, 75% reduction in infectiousness, and mean durations of IMP of at least 50 y were assumed. This analysis indicates that routine vaccination of toddlers against hepatitis A virus would be cost-effective in Mexico using a single-dose vaccination strategy. However, the cost-effectiveness of a second dose depends on the assumptions of additional protection by IMP and the time horizon over which the analysis is performed.
authors.affiliation: a Economics Department , GSK Vaccines , Wavre , Belgium.
authors.forename: Desmond
authors.initials: D
authors.lastname: Curran
authors.affiliation: b GSK Vaccines , Wavre , Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: de Ridder
authors.affiliation: b GSK Vaccines , Wavre , Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Van Effelterre
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003362:Cost-Benefit Analysis; D005260:Female; D006506:Hepatitis A / Q000191:economics / Q000453:epidemiology* / Q000517:prevention & control*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage* / Q000191:economics / Q000276:immunology*; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008962:Models, Theoretical; D019057:Quality-Adjusted Life Years; D055815:Young Adult
chemical_list: D022362:Hepatitis A Vaccines
keywords: Immune memory; cost-effectiveness; hepatitis A; mathematical model; number of doses; vaccination