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Ann Epidemiol
. 2025 Jun 19:S1047-2797(25)00132-2.
doi: 10.1016/j.annepidem.2025.06.010. Online ahead of print. Changed epidemiology of influenza and RSV hospitalizations after the emergence of SARS-CoV-2 in Norway, 2017 - 2024
Håkon Bøås 1 , Elina Seppälä 2 , Lamprini Veneti 3 , Jeanette Stålcrantz 2 , Jacob Dag Berild 2 , Jesper Dahl 2 , Trine Hessevik Paulsen 2
Affiliations
Background: Many countries reported missing and atypical influenza and RSV seasons during the COVID-19 pandemic. Here we describe the incidence and seasonality of COVID-19, influenza, and RSV hospitalizations in Norway between 2017-2024, and the disease burden between 2022-2024.
Methods: Using nationwide data on ICD-10 discharge codes, procedure codes and laboratory results, we calculate the incidence of COVID-19, influenza, and RSV hospitalizations, by age group, week and surveillance year between January 2017 to April 2024, and report proportions receiving intensive care, deaths and length of stay between 2022-2024.
Results: The transmission of influenza and RSV was interrupted the first year of the COVID-19 pandemic and reemerged with epidemics outside of the normal seasonality in 2021/2022, after COVID-19 restrictions were removed. Between 2022-2024, COVID-19 was a greater contributor to hospitalizations than influenza and RSV, with higher mortality rate within two weeks of admission. The use of ventilatory support/intensive care admission was highest among patients hospitalized with RSV.
Conclusion: The transmission of influenza and RSV was interrupted during the first year of the COVID-19 pandemic, followed by an unusual seasonality. Although many hospitalizations are caused by RSV and influenza, COVID-19 was the largest contributor of these three to hospital burden in the first years with co-circulation.
Keywords: COVID-19; Disease Burden; Length of stay; RSV, Respiratory Syncytial Virus; influenza.
. 2025 Jun 19:S1047-2797(25)00132-2.
doi: 10.1016/j.annepidem.2025.06.010. Online ahead of print. Changed epidemiology of influenza and RSV hospitalizations after the emergence of SARS-CoV-2 in Norway, 2017 - 2024
Håkon Bøås 1 , Elina Seppälä 2 , Lamprini Veneti 3 , Jeanette Stålcrantz 2 , Jacob Dag Berild 2 , Jesper Dahl 2 , Trine Hessevik Paulsen 2
Affiliations
- PMID: 40543765
- DOI: 10.1016/j.annepidem.2025.06.010
Background: Many countries reported missing and atypical influenza and RSV seasons during the COVID-19 pandemic. Here we describe the incidence and seasonality of COVID-19, influenza, and RSV hospitalizations in Norway between 2017-2024, and the disease burden between 2022-2024.
Methods: Using nationwide data on ICD-10 discharge codes, procedure codes and laboratory results, we calculate the incidence of COVID-19, influenza, and RSV hospitalizations, by age group, week and surveillance year between January 2017 to April 2024, and report proportions receiving intensive care, deaths and length of stay between 2022-2024.
Results: The transmission of influenza and RSV was interrupted the first year of the COVID-19 pandemic and reemerged with epidemics outside of the normal seasonality in 2021/2022, after COVID-19 restrictions were removed. Between 2022-2024, COVID-19 was a greater contributor to hospitalizations than influenza and RSV, with higher mortality rate within two weeks of admission. The use of ventilatory support/intensive care admission was highest among patients hospitalized with RSV.
Conclusion: The transmission of influenza and RSV was interrupted during the first year of the COVID-19 pandemic, followed by an unusual seasonality. Although many hospitalizations are caused by RSV and influenza, COVID-19 was the largest contributor of these three to hospital burden in the first years with co-circulation.
Keywords: COVID-19; Disease Burden; Length of stay; RSV, Respiratory Syncytial Virus; influenza.