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. 2021 Aug 30;50(4):1124-1133.
doi: 10.1093/ije/dyab081.

Interactions between SARS-CoV-2 and influenza, and the impact of coinfection on disease severity: a test-negative design

Julia Stowe  1 , Elise Tessier  1 , H Zhao  1 , Rebecca Guy  2 , Berit Muller-Pebody  2 , Maria Zambon  3 , Nick Andrews  4 , Mary Ramsay  1 , Jamie Lopez Bernal  1
Affiliations

Interactions between SARS-CoV-2 and influenza, and the impact of coinfection on disease severity: a test-negative design

Julia Stowe et al. Int J Epidemiol. .

Abstract

Background: The impact of SARS-CoV-2 alongside influenza is a major concern in the northern hemisphere as winter approaches.

Methods: Test data for influenza and SARS-CoV-2 from national surveillance systems between 20 January 2020 and 25 April 2020 were used to estimate influenza infection on the risk of SARS-CoV-2 infection. A test-negative design was used to assess the odds of SARS-CoV-2 in those who tested positive for influenza compared with those who tested negative. The severity of SARS-CoV-2 was also assessed using univariable and multivariable analyses.

Results: The risk of testing positive for SARS-CoV-2 was 58% lower among influenza-positive cases and patients with a coinfection had a risk of death of 5.92 (95% confidence interval: 3.21-10.91) times greater than among those with neither influenza nor SARS-CoV-2. The odds of ventilator use or death and intensive care unit admission or death were greatest among coinfected patients.

Conclusions: Coinfection of these viruses could have a significant impact on morbidity, mortality and health-service demand.

Keywords: SARS-CoV-2; coinfection; epidemiology; influenza; interaction.

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Figures

Figure 1
Figure 1
Distribution of SARS-CoV-2, influenza and coinfected cases in England from between 20 January 2020 and 25 April 2020 (Weeks 1–17)
Figure 2
Figure 2
The odds and 95% confidence intervals* of death, ventilator use and ICU admission by influenza/SARS-CoV-2 status compared with individuals with no infection in England from 20 January 2020 to 25 April 2020
See this image and copyright information in PMC

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