Influenza Activity and Composition of the 2022-23 Influenza Vaccine - United States, 2021-22 Season

MMWR Morb Mortal Wkly Rep. 2022 Jul 22;71(29):913-919. doi: 10.15585/mmwr.mm7129a1.


Before the emergence of SARS-CoV-2, the virus that causes COVID-19, influenza activity in the United States typically began to increase in the fall and peaked in February. During the 2021-22 season, influenza activity began to increase in November and remained elevated until mid-June, featuring two distinct waves, with A(H3N2) viruses predominating for the entire season. This report summarizes influenza activity during October 3, 2021-June 11, 2022, in the United States and describes the composition of the Northern Hemisphere 2022-23 influenza vaccine. Although influenza activity is decreasing and circulation during summer is typically low, remaining vigilant for influenza infections, performing testing for seasonal influenza viruses, and monitoring for novel influenza A virus infections are important. An outbreak of highly pathogenic avian influenza A(H5N1) is ongoing; health care providers and persons with exposure to sick or infected birds should remain vigilant for onset of symptoms consistent with influenza. Receiving a seasonal influenza vaccine each year remains the best way to protect against seasonal influenza and its potentially severe consequences.

MeSH terms

  • COVID-19*
  • Humans
  • Influenza A Virus, H3N2 Subtype / genetics
  • Influenza A Virus, H5N1 Subtype*
  • Influenza B virus / genetics
  • Influenza Vaccines*
  • Influenza, Human* / epidemiology
  • Influenza, Human* / prevention & control
  • Population Surveillance
  • SARS-CoV-2
  • Seasons
  • United States / epidemiology


  • Influenza Vaccines