Update: Influenza Activity in the United States During the 2016–17 Season and Composition of the 2017–18 Influenza Vaccine

Lenee Blanton, MPH; Noreen Alabi, MPH; Desiree Mustaquim, MPH; Calli Taylor, MPH; Krista Kniss, MPH; Natalie Kramer; Alicia Budd, MPH; Shikha Garg, MD; Charisse N. Cummings, MPH; Jessie Chung, MPH; Brendan Flannery, PhD; Alicia M. Fry, MD; Wendy Sessions, MPH; Rebecca Garten, PhD; Xiyan Xu, MD; Anwar Isa Abd Elal; Larisa Gubareva, PhD; John Barnes, PhD; Vivien Dugan, PhD; David E. Wentworth, PhD; Erin Burns, MA; Jacqueline Katz, PhD; Daniel Jernigan, MD; Lynnette Brammer, MPH


Morbidity and Mortality Weekly Report. 2017;66(25):668-676. 

In This Article

Abstract and Introduction


During the 2016–17 influenza season (October 2, 2016–May 20, 2017) in the United States, influenza activity* was moderate. Activity remained low through November, increased during December, and peaked in February nationally, although there were regional differences in the timing of influenza activity. Influenza A(H3N2) viruses predominated through mid-March and were predominant overall for the season, but influenza B viruses were most commonly reported from late March through May. This report summarizes influenza activity in the United States during October 2, 2016–May 20, 2017 and updates the previous summary.[1]

*The CDC influenza surveillance system collects five categories of information from eight data sources: 1) viral surveillance (U.S. World Health Organization collaborating laboratories, the National Respiratory and Enteric Virus Surveillance System, and novel influenza A virus case reporting); 2) outpatient illness surveillance (U.S. Outpatient Influenza-Like Illness Surveillance Network); 3) mortality (the National Center for Health Statistics Mortality Surveillance System and influenza-associated pediatric mortality reports); 4) hospitalizations (FluSurv-NET, which includes the Emerging Infections Program and surveillance in three additional states); and 5) summary of the geographic spread of influenza (state and territorial epidemiologist reports). https://www.cdc.gov/flu/weekly/fluactivitysurv.htm.
Data as of June 9, 2017.