Cost-effectiveness of childhood hepatitis A vaccination in Argentina: a second dose is warranted.

OBJECTIVES To investigate the cost-effectiveness of childhood vaccination against hepatitis A in the five geographic regions of Argentina, and to determine whether adding a second dose to the current one-dose schedule would provide health gains justifying its added cost. METHODS A Markov model was used to consider four immunization options for the 2005 birth cohort: (1) no vaccination; (2) vaccination at 12 months of age, (3) vaccinations at 12 and 72 months of age; or (4) vaccinations at 12 and 18 months of age. Hepatitis A costs and consequences were predicted over 50 years. The cost-effectiveness of first and second vaccine doses was assessed through a range of vaccine prices and assumptions regarding the duration of vaccine protection. Costs and health gains (measured in quality-adjusted life years) were adjusted to present values using a 3% annual discount rate. RESULTS The one-dose vaccination policy is predicted to reduce each birth cohort member's 50-year probability of overt hepatitis A from 7.2% to 4.1%. A second dose would reduce the probability to between 2.0% and 2.2%. Vaccination at 12 months of age, at 12 and 72 months, or at 12 and 18 months would reduce cases among personal contacts by 82%, 87%, and 92%, respectively. The first vaccine dose would meet accepted standards of cost-effectiveness in each region, and reduce costs in the Northeast, Central, and South regions. Adding a second dose at age 18 months would be cost-effective in each region, and further reduce costs in the Cuyo region. If the duration of protection with one dose is less than anticipated, the second dose would be more cost-effective. CONCLUSIONS Greater health gains are derived from the first than second hepatitis A vaccine dose. However, this analysis supports the cost-effectiveness of providing both first and second doses to Argentina's children.