COST-EFFECTIVENESS OF GROUP A STREPTOCOCCAL VACCINATION IN THE UNITED STATES

Purpose: To assess the cost-effectiveness of a group A streptococcal (GAS) vaccination program for 4 year-old children in the U.S.

Design: A Markov model with a 1-year cycle length was constructed to evaluate two strategies: 1) GAS vaccination of 4-year old children in the U.S.; and 2) no GAS vaccination program.  We analyzed the costs, health benefits, and cost-effectiveness of vaccinating a hypothetical birth cohort of 4 million children followed over a 10-year period from the societal perspective.  Future costs and benefits were discounted at 3%.  Estimates for probabilities, costs, and utilities for disease and vaccine-related outcomes were based on published studies, meeting abstracts, and expert panel input.  Outcomes included total costs in 2008 US$, cases of GAS prevented (including pharyngitis, skin/soft tissue infections, invasive disease, and rheumatic fever), cost per case prevented and cost per quality-adjusted life year (QALY) saved.

Results: In the absence of a GAS vaccination program, ~1.1 million cases of GAS-related disease occurred over a 10-yr period.  If 80% of children received a 3-dose GAS vaccination series, approximately 513,000 cases of GAS disease could be prevented (510,000 cases of pharyngitis, 3,000 skin/soft tissue infections, 160 invasive disease cases, 16 acute rheumatic fever cases).  At a vaccine cost of $50 per dose, the total cost of a vaccination program would be $775 million; however, $146 million would be saved due to disease averted.  At base case estimates, the cost per case prevented and cost per QALY saved were $970 and $208,000, respectively.   Our results were most sensitive to assumptions about the incidence of pharyngitis and vaccine costs.  The cost per QALY of a GAS vaccination program fell below $100,000 if pharyngitis incidence was greater than 1.5x base case estimates or if the cost per vaccine dose was less than $22. 

Conclusion: A GAS vaccination program for 4 yr old children could prevent over ½ million cases of GAS-related disease.  Depending on the cost of vaccination and the incidence of pharyngitis, a GAS vaccination program may or may not be cost-effective in the U.S.