Respiratory syncytial virus as an independent driver of a subsequent influenza epidemic in Berlin before and after the COVID-19 pandemic

Nicolas Terliesner; Dariusz Lesniowski; Nadine Unterwalder; Horst von Bernuth; Martin Grieser; Alexander Gratopp; Marcus A Mall; Tilmann Kallinich

doi:10.1016/j.ijid.2026.108741

Respiratory syncytial virus as an independent driver of a subsequent influenza epidemic in Berlin before and after the COVID-19 pandemic

Int J Infect Dis. 2026 Apr 28:168:108741. doi: 10.1016/j.ijid.2026.108741. Online ahead of print.

Authors

Nicolas Terliesner¹, Dariusz Lesniowski², Nadine Unterwalder³, Horst von Bernuth⁴, Martin Grieser², Alexander Gratopp², Marcus A Mall⁵, Tilmann Kallinich⁶

Affiliations

¹ Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Cardiac Intensive Care Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK. Electronic address: nicolas.terliesner@charite.de.
² Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
³ Labor Berlin GmbH, Berlin, Germany.
⁴ Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Labor Berlin GmbH, Berlin, Germany.
⁵ Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Center for Child and Adolescent Health (DZKJ), partner site Berlin, Berlin, Germany; German Center for Lung Research (DZL), associated partner site Berlin, Berlin, Germany.
⁶ Department of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Center for Child and Adolescent Health (DZKJ), partner site Berlin, Berlin, Germany; Deutsches Rheumaforschungszentrum, An Institute of the Leibniz Association, Berlin, Germany.

PMID: 42061498
DOI: 10.1016/j.ijid.2026.108741

Abstract

Objectives: Following the withdrawal of non-pharmaceutical interventions (NPI) implemented during the coronavirus disease 2019 (COVID-19) pandemic, the resurgence of respiratory viral infections in children deviated from established pre-pandemic seasonal patterns. We aimed to use the disruption in the seasonality of respiratory viral infections caused by NPI measures to identify key drivers of seasonality before and since the COVID-19 pandemic.

Methods: We applied a Bayesian model to crossover-predict the incidence of infections with human metapneumovirus, influenza viruses, and respiratory syncytial viruses (RSV) in children admitted to Berlin University Children's Hospital in the pre-pandemic and in the post-pandemic era (from 08/2021) after training based on data from the respective other period. We analyzed the effect of environmental and viral coefficients on the accuracy of prediction.

Results: Incidence of infection with respiratory viruses was accurately predicted both for the pre-pandemic and the post-pandemic era. After excluding autoregression, no single factor independently predicted the incidence of infection with metapneumovirus or RSV. Incidence of infection with influenza virus was predicted by a previous RSV epidemic as a single coefficient.

Conclusion: Our data show that it takes several years before seasonal patterns of common viral respiratory infections are reestablished. However, drivers of the abnormal seasonality of respiratory virus infections in children following the lifting of NPI measures during the COVID-19 pandemic did not differ from drivers of the pre-pandemic seasonality. Both environmental factors and viral interference shape the seasonal pattern of respiratory viral infections. Incidence patterns of influenza seem to be more prone to virus-virus interactions than those of RSV.

Keywords: Bayes; Influenza; Metapneumovirus; Respiratory syncytial virus; Respiratory virus infection; Viral interference.