Influenza Activity and Composition of the 2022–23 Influenza Vaccine

United States, 2021-22 Season

Angiezel Merced-Morales, MPH; Peter Daly, MPH; Anwar Isa Abd Elal; Noreen Ajayi, MPH; Ekow Annan, MPH; Alicia Budd, MPH; John Barnes, PhD; Arielle Colon, MPH; Charisse N. Cummings, MPH; A. Danielle Iuliano, PhD; Juliana DaSilva, MA; Nick Dempster, MPH; Shikha Garg, MD; Larisa Gubareva, PhD; Daneisha Hawkins, MPH; Amanda Howa, MPH; Stacy Huang, MPH; Marie Kirby, PhD; Krista Kniss, MPH; Rebecca Kondor, PhD; Jimma Liddell; Shunte Moon, PhD; Ha T. Nguyen; Alissa O'Halloran, MSPH; Catherine Smith, MS; Thomas Stark, PhD; Katie Tastad, MPH; Dawud Ujamaa, MS; Dave E. Wentworth, PhD; Alicia M. Fry, MD; Vivien G. Dugan, PhD; Lynnette Brammer, MPH


Morbidity and Mortality Weekly Report. 2022;71(29):913-919. 

In This Article

Abstract and Introduction


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.

The United States influenza surveillance system is a collaborative effort between CDC and its many partners in state, local, and territorial health departments, public health and clinical laboratories, vital statistics offices, health care providers, hospitals, clinics, emergency departments, and long-term care facilities. This report is a summary of the 2021–22 influenza season. This report was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.

*These authors contributed equally to this report.
45 C.F.R. part 46, 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.