An economic evaluation of universal infant vaccination strategies against hepatitis B in Thailand: an analytic decision approach to cost-effectiveness.

To evaluate the cost-effectiveness of four infant vaccination strategies aimed at protecting the Thai population against hepatitis B virus (HBV) infection, vaccination and giving hepatitis B im- munoglobulin (HBIg) to high-risk infants were compared with universal vaccination of infants and no vaccination. An analytic decision model was used to estimate the clinical and economic conse- quences of HBV for a hypothetical cohort of newborns for each of the immunization strategies. The model focused on the numbers and the costs of cases prevented. The decision model examined four different HBV management strategies: 1. screening for HBsAg, and vaccination; 2. screening for HBsAg, then HBeAg, and vaccination; 3. universal vaccination of all neonates; and 4. no vacci- nation. The cost-effectiveness per case prevented for Strategy 1 was 292.79 baht; for Strategy 2, 264.34 baht; for Strategy 3, 151.05 baht; and for Strategy 4, 0 baht. The incremental cost compar- ing Strategy 3 to Strategy 4 was 6,521 baht; comparing Strategy 2 to Strategy 3, 20,000 baht; and comparing Strategy 1 to Strategy 2, 95,000 baht. There is no socially acceptable threshold value for cost per case prevented to guide decisions on funding health care interventions. Strategy 3 should certainly be continued. Nevertheless, based on these results, Strategy 2 may be considered, de- spite the incremental cost being about 2 times that of Strategy 3, as it might represent a worthwhile investment of public funds.