Impact of Vaccine Schedule Change on Pertussis Epidemiology in France: A Modelling and Serological Study

Background: In 2013, France modified its pertussis vaccination schedule to remove one dose at 3 months of age and change the booster from 16 11 months. We aimed assess subsequent impact on epidemiology in France. Methods: analysed PCR test results nasopharyngeal swabs (N=7493) collected symptomatic outpatients aged 2-20 years old between 2012 2019 France. developed a Poisson regression model which number positive cases by year depended year, group, population size each group proxy waning immunity that could vary with vaccine schedule. also compared anti-pertussis toxin (PT) antibody levels 315 children born before after change. Findings: The best fitted 2012-2018 epidemiological data supported faster following new Four vaccination, risk developing was 2.1 (95% CI, 1.7-2.2) times higher for vaccinated according than those previous correctly predicted distribution 2019. Anti-PT IgG were significantly lower implementation schedule, before. Interpretation: A shorter-lived protection induced 2/4+11 recommended since 2013 is associated an increase 2-5-year olds. Funding Statement: This project funded INCEPTION interdisciplinary Institut Pasteur, “Understanding whooping cough resurgence Europe combining genomic, sociological approaches” (French Government Investissements d’Avenir grant ANR-16-CONV-0005). work received financial support French Government’s Investissement program, Laboratoire d’Excellence ‘Integrative Biology Emerging Infectious Diseases’ (grant n_ANR-10-LABX-62-IBEID). Institutional provided Pasteur Sante publique France. Declaration Interests: None declare. Ethics Approval collection approval supervisory ethics authority (CNIL, n°1474593), approved local Review board (N° 2020 1028160733). All processing storage comply General Data Protection Regulation (GDPR) ethical standards National Research Committee. study conducted accordance Helsinki Declaration, informed consent obtained patient’s guardians.