Reassessing the cost-effectiveness of meningococcal serogroup C conjugate (MCC) vaccines using a transmission dynamic model.

BACKGROUND: The meningococcal serogroup C conjugate (MCC) vaccination program has successfully reduced morbidity and mortality from serogroup C disease in England and Wales, owing to high short-term vaccine effectiveness and substantial herd immunity. The latter effect was not accounted for in the previous economic analysis of the MCC program.
METHODS: The authors applied a transmission dynamic model, which accounts for herd immunity, to reevaluate the cost-effectiveness of MCC vaccination. The direct and indirect benefits of the MCC vaccine strategy implemented in England and Wales were compared. The cost-effectiveness of alternative MCC vaccine strategies, including future changes to the current schedule, were evaluated.
RESULTS: The authors found that including herd immunity improved the average cost-effectiveness ratio in all cases, although the extent depended on the vaccine strategy considered. Incremental analysis showed that those strategies that offered 1 dose early in the 2nd year of life dominated strategies that offered 3 doses of vaccine in infancy and that catch-up vaccination up to the age of 18 years was also highly attractive. Furthermore, the authors analyzed the effect of future changes to the routine vaccine schedule and predicted that shifting the age at routine vaccination from 2, 3, and 4 months (3 doses) to 12 months (1 dose) resulted in a net gain in the total number of cases prevented with only a few extra cases occurring in children under 1 year of age. This program dominated the current strategy.
CONCLUSIONS: Models that do not include the indirect effects of vaccination will underestimate the impact of MCC vaccination and may lead to distorted decision making.