Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jul 23;70(29):1013-1019.
doi: 10.15585/mmwr.mm7029a1.

Changes in Influenza and Other Respiratory Virus Activity During the COVID-19 Pandemic - United States, 2020-2021

Sonja J Olsen, Amber K Winn, Alicia P Budd, Mila M Prill, John Steel, Claire M Midgley, Krista Kniss, Erin Burns, Thomas Rowe, Angela Foust, Gabriela Jasso, Angiezel Merced-Morales, C Todd Davis, Yunho Jang, Joyce Jones, Peter Daly, Larisa Gubareva, John Barnes, Rebecca Kondor, Wendy Sessions, Catherine Smith, David E Wentworth, Shikha Garg, Fiona P Havers, Alicia M Fry, Aron J Hall, Lynnette Brammer, Benjamin J Silk

Changes in Influenza and Other Respiratory Virus Activity During the COVID-19 Pandemic - United States, 2020-2021

Sonja J Olsen et al. MMWR Morb Mortal Wkly Rep. .

Abstract

The COVID-19 pandemic and subsequent implementation of nonpharmaceutical interventions (e.g., cessation of global travel, mask use, physical distancing, and staying home) reduced transmission of some viral respiratory pathogens (1). In the United States, influenza activity decreased in March 2020, was historically low through the summer of 2020 (2), and remained low during October 2020-May 2021 (<0.4% of respiratory specimens with positive test results for each week of the season). Circulation of other respiratory pathogens, including respiratory syncytial virus (RSV), common human coronaviruses (HCoVs) types OC43, NL63, 229E, and HKU1, and parainfluenza viruses (PIVs) types 1-4 also decreased in early 2020 and did not increase until spring 2021. Human metapneumovirus (HMPV) circulation decreased in March 2020 and remained low through May 2021. Respiratory adenovirus (RAdV) circulated at lower levels throughout 2020 and as of early May 2021. Rhinovirus and enterovirus (RV/EV) circulation decreased in March 2020, remained low until May 2020, and then increased to near prepandemic seasonal levels. Circulation of respiratory viruses could resume at prepandemic levels after COVID-19 mitigation practices become less stringent. Clinicians should be aware of increases in some respiratory virus activity and remain vigilant for off-season increases. In addition to the use of everyday preventive actions, fall influenza vaccination campaigns are an important component of prevention as COVID-19 mitigation measures are relaxed and schools and workplaces resume in-person activities.

PubMed Disclaimer

Conflict of interest statement

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. John Steel reported intellectual property from patent positions on universal influenza virus vaccines; he receives no income from the patent positions. No other potential conflicts of interest were disclosed.

Figures

FIGURE 1
FIGURE 1
Number of specimens tested and the percentage of positive tests for influenza viruses, respiratory syncytial virus, common human coronaviruses, parainfluenza viruses, human metapneumovirus, respiratory adenoviruses, and rhinoviruses/enteroviruses, by year — United States, 2016–2021
FIGURE 2
FIGURE 2
Percentage of specimens testing positive for influenza viruses, respiratory syncytial virus, common human coronaviruses, parainfluenza viruses, human metapneumovirus, respiratory adenoviruses, and rhinoviruses/enteroviruses, by month — United States, 2016–2017 through 2020–2021
See this image and copyright information in PMC

References

    1. Haddadin Z, Schuster JE, Spieker AJ, et al. Acute respiratory illnesses in children in the SARS-CoV-2 pandemic: prospective multicenter study. Pediatrics 2021;e2021051462. 10.1542/peds.2021-051462 - DOI - PMC - PubMed
    1. Olsen SJ, Azziz-Baumgartner E, Budd AP, et al. Decreased influenza activity during the COVID-19 pandemic—United States, Australia, Chile, and South Africa, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1305–9. 10.15585/mmwr.mm6937a6 - DOI - PMC - PubMed
    1. Mott JA, Fry AM, Kondor R, Wentworth DE, Olsen SJ. Re-emergence of influenza virus circulation during 2020 in parts of tropical Asia: implications for other countries. Influenza Other Respir Viruses 2021;15:415–8. 10.1111/irv.12844 - DOI - PMC - PubMed
    1. Laurie KL, Rockman S. Which influenza viruses will emerge following the SARS-CoV-2 pandemic? Influenza Other Respir Viruses 2021. Epub May 6, 2021. 10.1111/irv.12844 - DOI - PMC - PubMed
    1. Grohskopf LA, Alyanak E, Broder KR, et al. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices—United States, 2020–21 Influenza Season. MMWR Recomm Rep 2020;69:(No. RR-8). 10.15585/mmwr.rr6908a1 - DOI - PMC - PubMed

MeSH terms