Association between the COVID-19 pandemic and pertussis derived from multiple nationwide data sources, France, 2013 to 2020.

BackgroundInterventions to mitigate the COVID-19 pandemic may impact other respiratory diseases.AimsWe aimed to study the course of pertussis in France over an 8-year period including the beginning of the COVID-19 pandemic and its association with COVID-19 mitigation strategies, using multiple nationwide data sources and regression models.MethodsWe analysed the number of French pertussis cases between 2013 and 2020, using PCR test results from nationwide outpatient laboratories (Source 1) and a network of the paediatric wards from 41 hospitals (Source 2). We also used reports of a national primary care paediatric network (Source 3). We conducted a quasi-experimental interrupted time series analysis, relying on negative binomial regression models. The models accounted for seasonality, long-term cycles and secular trend, and included a binary variable for the first national lockdown (start 16 March 2020).ResultsWe identified 19,039 pertussis cases from these data sources. Pertussis cases decreased significantly following the implementation of mitigation measures, with adjusted incidence rate ratios of 0.10 (95% CI: 0.04-0.26) and 0.22 (95% CI: 0.07-0.66) for Source 1 and Source 2, respectively. The association was confirmed in Source 3 with a median of, respectively, one (IQR: 0-2) and 0 cases (IQR: 0-0) per month before and after lockdown (p = 0.0048).ConclusionsThe strong reduction in outpatient and hospitalised pertussis cases suggests an impact of COVID-19 mitigation measures on pertussis epidemiology. Pertussis vaccination recommendations should be followed carefully, and disease monitoring should be continued to detect any resurgence after relaxation of mitigation measures.

Bronchiolitis epidemics in France during the SARS-CoV-2 pandemic: The 2020-2021 and 2021-2022 seasons.

OBJECTIVES: We described bronchiolitis epidemics during the 2020-2021 and 2021-2022 seasons in France and their interaction with the COVID outbreak. PATIENTS AND METHODS: Data on family physician (FP) visits, emergency department (ED) visits, hospitalizations for bronchiolitis for children˂2 years, and hospital virological data were analyzed and compared with previous seasons (2015-2020). RESULTS: The 2020-2021 epidemic arrived very late, and its impact was lower than in previous seasons (2015-2020) (FP visits: -23%, ED visits: -38%, and hospitalizations: -30%). The 2021-2022 epidemic started early (week 40) and lasted for a relatively long time (13 weeks). The impact was higher than in 2015-2020 (FP visits: +13%, ED visits: +34%, hospitalizations: +28%). CONCLUSION: Findings from the 2020-2021 epidemic may be linked to the implementation of non-pharmaceutical COVID-19 prevention measures. For 2021-2022, findings may be linked to an "immunity debt" resulting from the lower impact of the previous season.