1. Seasonality and severity of respiratory syncytial virus during the COVID-19 pandemic: a dynamic cohort study
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Vieri Lastrucci, Martina Pacifici, Monia Puglia, Giorgia Alderotti, Elettra Berti, Marco Del Riccio, Guglielmo Bonaccorsi, Maria Moriondo, Massimo Resti, Diego Peroni, Marco Martini, Chiara Azzari, Rosa Gini, and Fabio Voller
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Respiratory syncytial virus ,Seasonality ,Clinical severity ,Children ,COVID-19 pandemic ,Cohort study ,Infectious and parasitic diseases ,RC109-216 - Abstract
Objectives: To investigate seasonality, epidemiologic characteristics, and clinical severity variations of respiratory syncytial virus (RSV)-associated hospitalizations following the easing of COVID-19 restrictions in Tuscany, Italy, up to the 2022-2023 season. Methods: From 2017 to 2023, a dynamic cohort consisting of all resident children aged ≤2 years was followed up in regional registries. The person-time incidence rate of RSV-associated hospitalizations per 1,000 person-years and risk of severe hospitalization (intensive care unit, continuous positive airway pressure, or mechanical ventilation) per 100 RSV hospitalizations were calculated. RSV seasonality was investigated with retrospective methods. Results: A total of 193,244 children were followed up. After the easing of restrictions, RSV epidemics showed earlier seasonality and shorter duration compared with pre-pandemic (2017 to 2019), with this deviation decreased in 2022-2023. In 2021-2022 and 2022-2023, the incidence rate of RSV-associated hospitalizations significantly increased compared with pre-pandemic (2022-2023 risk ratio 3.6, 95% confidence interval 3.3-4.0), with larger increases among older age groups. Among hospitalized children, only those aged ≥12 months showed an increased risk of severe hospitalization, particularly during 2021-2022 (risk ratio 4.7, 95% confidence interval 1.5-24.3). Conclusions: Our findings suggest a gradual return of RSV epidemics to the pre-pandemic pattern, although relevant increases in disease incidence persist. Reduced regular RSV exposure among older children may lead to declining immunity and increased severe outcome risks.
- Published
- 2024
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