Outcomes of SARS-CoV-2 Omicron Variant Infections Compared With Seasonal Influenza and Respiratory Syncytial Virus Infections in Adults Attending the Emergency Department: A Multicenter Cohort Study.

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  • Additional Information
    • Source:
      Publisher: Oxford University Press Country of Publication: United States NLM ID: 9203213 Publication Model: Print Cited Medium: Internet ISSN: 1537-6591 (Electronic) Linking ISSN: 10584838 NLM ISO Abbreviation: Clin Infect Dis Subsets: MEDLINE
    • Publication Information:
      Publication: Jan. 2011- : Oxford : Oxford University Press
      Original Publication: Chicago, IL : The University of Chicago Press, c1992-
    • Subject Terms:
      Respiratory Syncytial Virus Infections* ; Influenza, Human*/epidemiology ; COVID-19*/epidemiology ; Respiratory Syncytial Virus, Human*; Adult ; Humans ; SARS-CoV-2 ; Cohort Studies ; Seasons ; Emergency Service, Hospital
    • Abstract:
      Background: There is a controversy over the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in an era of less virulent variants and an increasing population immunity. We compared outcomes in adults attending the emergency department (ED) with an Omicron, influenza, or respiratory syncytial virus (RSV) infection.
      Methods: Retrospective multicenter cohort study including adults attending the ED in 6 acute care hospitals in Stockholm County, Sweden, with an Omicron, influenza, or RSV infection during 2021-2022 and 2015-2019. During 2021-2022, patients were tested for all 3 viruses by multiplex polymerase chain reaction (PCR) testing. The primary outcome was 30-day all-cause mortality. Secondary outcomes were 90-day all-cause mortality, hospitalization, and intensive care unit (ICU) admission.
      Results: A total of 6385 patients from 2021-2022 were included in the main analyses: 4833 Omicron, 1099 influenza, and 453 RSV. The 30-day mortality was 7.9% (n = 381) in the Omicron, 2.5% (n = 28) in the influenza, and 6.0% (n = 27) in the RSV cohort. Patients with Omicron had an adjusted 30-day mortality odds ratio (OR) of 2.36 (95% confidence interval [CI] 1.60-3.62) compared with influenza and 1.42 (95% CI .94-2.21) compared with RSV. Among unvaccinated Omicron patients, stronger associations were observed compared with both influenza (OR 5.51 [95% CI 3.41-9.18]) and RSV (OR 3.29 [95% CI 2.01-5.56]). Similar trends were observed for secondary outcomes. Findings were consistent in comparisons with 5709 pre-pandemic influenza 995 RSV patients.
      Conclusions: In patients attending the ED, infections with Omicron were both more common and associated with more severe outcomes compared with influenza and RSV, in particular among unvaccinated patients.
      Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
      (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)
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    • Grant Information:
      Swedish Research Council; 101046016 European Union's Horizon Europe Research and Innovation Program
    • Contributed Indexing:
      Keywords: Omicron; SARS-CoV-2; emergency department; influenza; respiratory syncytial virus
    • Subject Terms:
      SARS-CoV-2 variants
    • Publication Date:
      Date Created: 20231026 Date Completed: 20240412 Latest Revision: 20240412
    • Publication Date:
      20240412
    • Accession Number:
      PMC11006100
    • Accession Number:
      10.1093/cid/ciad660
    • Accession Number:
      37883521