Re-Establishing the Societal Value of Pediatric Combination Vaccines

Abstract

observational studies also confirmed the indirect protection provided by rotavirus vaccination in countries where rotavirus vaccination programmes have been introduced. France has not yet implemented such a programme. Previously reported models in France do not include herd protection, thus underestimating the effectiveness of vaccination. Our study uses a dynamic transmission model to account for herd protection and therefore better predict the effect of an oral rotavirus pentavalent vaccination programme in France. Methods:We developed a dynamic model to account for susceptibility of rotavirus infection as a function of both age and the number of previous infections. It was parameterized with French data on rotavirus gastro-enteritis (RVGE) incidence and age-specific contact rates. We evaluated the direct and indirect effects of vaccination on disease incidence and clinical outcomes. A three-dose vaccine course was assumed to be administered to 75% of infant annually. Results: Our model predicts that vaccination can reduce the burden of RVGE by 66% in the four years following vaccine introduction, gradually increasing to 73% in the long term for children under 5 years of age. Our calculations show that herd immunity accounts for 11% to 20% of the overall RVGE reduction in children. Incidence in the unvaccinated adult population would also be reduced by more than 40% through herd protection. Vaccination is also predicted to reduce pressure on the health care system with the model estimating an annual reduction of 84% and 82% in the number of hospitalization/nosocomial and outpatient visits for RVGE respectively. ConClusions: The use of dynamic models is critical to account for the indirect effects of rotavirus vaccination via herd protection and thus for policymakers to understand the true effectiveness of a country-wide rotavirus vaccination programme.