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Objectives: Economic analysis is an important component in formulating national policy. We evaluated the economic impact of hepatitis A vaccination of all US children ages 12 to 23 months as compared with no vaccination and with current implementation of the preexisting (issued in 1999), regional policy., Methods: We developed a Markov model of hepatitis A that followed a single cohort from birth in 2005 through death or age 95 years. From the societal perspective, the model compared the outcomes that resulted from routine vaccination at age 1 year to 2 scenarios: no hepatitis A vaccination and hepatitis A vaccination at levels observed in 2003 under the preexisting policy. We evaluated the economic impact of vaccination nationwide, in areas where vaccination was already recommended, and in areas where no previous recommendation existed., Results: Without childhood vaccination, the approximately 4 million children in the 2005 birth cohort would be expected over their lifetimes to have 199,000 hepatitis A virus infections, including 74,000 cases of acute hepatitis A and 82 deaths, resulting in 134 million dollars in hepatitis A-related medical costs and productivity losses. Compared with no vaccination, routine vaccination at age 1 year would prevent 172,000 infections, at a cost of 28,000 dollars per quality-adjusted life year saved. Compared with maintaining the levels of hepatitis A vaccination under the preexisting regional policy, routine vaccination at age 1 year would prevent an additional 112,000 infections, at a cost of 45,000 dollars per quality-adjusted life year saved., Conclusions: The cost-effectiveness of nationwide hepatitis A vaccination compared with no vaccination, and the incremental cost-effectiveness of this recommendation compared with preexisting recommendations, is similar to that of other accepted public health interventions. In October 2005, the Advisory Committee on Immunization Practices recommended extending hepatitis A immunization to all US children ages 12 to 23 months.

Objectives: Because of the herd-immunity phenomenon, the benefits of immunization against hepatitis A extend beyond those received by those who are vaccinated. This analysis estimates the impact of herd immunity on the cost-effectiveness of routine hepatitis A immunization among US children., Patients and Methods: In an economic model, the costs and benefits of hepatitis A immunization were estimated for immunizing all US children at age 1 year over a 10-year period starting in 2005. The future burden of disease from hepatitis A was also estimated with this model, and the fraction that would be prevented by herd immunity was modeled by using a previously published analysis of the relationship between hepatitis A vaccination coverage and declines in hepatitis A incidence., Results: Without accounting for herd-immunity effects, the costs of routine immunization would average 32,000 dollars per quality-adjusted life-year gained for the first 10 cohorts immunized starting with the 2005 birth cohort. Herd-immunity effects would be expected to produce substantial additional benefits, lowering the cost of the immunization program to 1000 dollars per quality-adjusted life-year gained for the first 10 cohorts. Herd-immunity benefits would be greatest for the first few cohorts, more than doubling the benefits of immunization, and would decline over time. In a univariate sensitivity analysis, estimates were most sensitive to vaccination costs but remained below 20,000 dollars per quality-adjusted life-year under all of the assumptions., Conclusions: Herd-immunity effects more than double the savings from hepatitis A immunization during the first 10 years of the program. After accounting for these effects, immunization is close to cost-neutral on a cost-per-quality-adjusted-life-year basis.

The licensing of two inactivated hepatitis A vaccines for persons 2 years or older necessitates development of recommendations for pediatric use, as well as a review of the current indications for immune globulin (IG) in hepatitis A prophylaxis. Both vaccines are immunogenic and protective in children and adults. A single dose of vaccine induced antibody in 88% to 96% of subjects by 2 weeks and 97% to 100% by 1 month, and protected against subsequent hepatitis A virus (HAV) disease occurring 21 days after receipt of the dose in a community with endemic hepatitis A infection. However, completion of the full vaccine schedule is recommended to assure high antibody titers and likely long-term protection. The major pediatric indications for vaccine are: (1) travelers to areas with intermediate to high rates of endemic hepatitis A, (2) children living in defined and circumscribed communities with high endemic rates or periodic outbreaks of HAV infection, and (3) patients with chronic liver disease. Immune globulin is recommended for postexposure prophylaxis, as vaccine has not yet been demonstrated to be protective for this purpose. Except for travelers, recommendations for IG use are not changed from those in the current edition of the Red Book, and include contacts of cases in the home, child care centers, and other selected sites.