Analyzing the economic value of the hepatitis B--Haemophilus influenzae type B combination vaccine by reverse engineering a formulary selection algorithm.

Combination vaccines for pediatric immunization provide a means to reduce the number of separate injections required to immunize children. This paper reports the results of reverse engineering a vaccine selection algorithm to evaluate the economic value of a hepatitis B-Haemophilus influenzae type B combination vaccine that is currently under federal contract in the United States. This analysis captures the tradeoff between the cost assigned to administering an injection and the price of the vaccine that earns it a place in the lowest overall cost formulary. Given the current United States federally negotiated price for this combination vaccine (as of 9 August 2002), it provides a good economic value for those health-care providers or payers who value the cost associated with administering an injection to be at least US$ 4.02 or 5.01. These two values are a function of the number of doses of the combination vaccine required to be in the lowest overall cost formulary and whether the perinatal hepatitis B dose is administered. Moreover, as the cost of an injection increases, the combination vaccine provides a better value than monovalent vaccines.