Impact of vaccine schedule change on pertussis epidemiology in France: a modelling and serological study

Juliette Paireau (1, 2) , Sophie Guillot (3, 4) , Fatima Aït El Belghiti (5) , Soraya Matczak (3, 6) , Sabine Trombert-Paolantoni (7) , Véronique Jacomo (8) , Muhamed-Kheir Taha (9, 10) , Henrik Salje (2, 11) , Sylvain Brisse (3, 4) , Daniel Lévy-Bruhl (5) , Simon Cauchemez (2) , Julie Toubiana (3, 4, 6)

1 Direction des maladies infectieuses - Infectious Diseases Division [Saint-Maurice]
2 Modélisation mathématique des maladies infectieuses - Mathematical modelling of Infectious Diseases
3 Biodiversité et Epidémiologie des Bactéries pathogènes - Biodiversity and Epidemiology of Bacterial Pathogens
4 CNR - Centre national de Référence de la Coqueluche et autres Bordetelloses - National Reference Center for Whooping Cough and other Bordetella infections
5 Infections respiratoires et vaccination [Saint-Maurice]
6 Département de Pédiatrie et maladies infectieuses [CHU Necker]
7 Laboratoire CERBA [Saint Ouen l'Aumône]
8 Eurofins Biomnis
9 Infections Bactériennes Invasives - Invasive Bacterial Infections
10 CNR - Centre National de Référence des Méningocoques et Haemophilus influenzae - National Reference Center Meningococci and Haemophilus influenzae
11 CAM - University of Cambridge [UK]

Background: In 2013, France modified its pertussis vaccination schedule to remove one dose at 3 months of age and change the age of the booster dose from 16 to 11 months. We aimed to assess the subsequent impact on pertussis epidemiology in France. Methods: We analysed the PCR test results of nasopharyngeal swabs (N=7493) collected from symptomatic outpatients aged 2-20 years old between 2012 and 2019 in France. We developed a negative binomial regression model for the number of pertussis cases by year and age. The linear predictor included the year, the age group, the population size and a proxy of waning immunity that could vary with vaccine schedule. We also compared the anti-pertussis toxin (PT) antibody levels of 315 children born before and after the vaccine schedule change. Findings: The model that best fitted the 2012-2018 epidemiological data supported a faster waning of immunity following vaccination with the new vaccine schedule. Three years after vaccination, the risk of developing pertussis was 1.7 (95% CI, 1.4-2.0) times higher for children vaccinated according to the new schedule than those vaccinated according to the previous schedule. The model correctly predicted the age distribution of cases in 2019. Anti-PT IgG levels were significantly lower in children born after implementation of the new schedule, compared to children born before. Interpretation: A shorter-lived protection induced by the 2/4+11 vaccine schedule recommended in France since 2013 is associated with an increase of pertussis cases in 2-5-year olds.

Domaines: Santé publique et épidémiologie; Statistiques [stat]

Juliette Paireau, Sophie Guillot, Fatima Aït El Belghiti, Soraya Matczak, Sabine Trombert-Paolantoni, et al.. Impact of vaccine schedule change on pertussis epidemiology in France: a modelling and serological study. The Lancet Infectious Diseases, 2022, 22 (2), pp.265-273. ⟨10.1016/S1473-3099(21)00267-X⟩. ⟨pasteur-03694021⟩