Influenza Activity — United States, 2015–16 Season and Composition of the 2016–17 Influenza Vaccine

• DOI: 10.15585/mmwr.mm6522a3
• Publication Date: 2016-06-09T17:06:45Z
• Authors: Stacy L. Davlin; Lenee Blanton; Krista Kniss; Desiree Mustaquim; Sophie Smith; Natalie Kramer; Jessica Cohen; Charisse Nitura C...; Shikha Garg; Brendan Flannery; Alicia M. Fry; Lisa A. Grohskopf; Joseph Bresee; Teresa Wallis; Wendy Sessions; Rebecca Garten; Xiyan Xu; Anwar Isa Abd Elal; Larisa Gubareva; John Barnes; David E. Wentworth; Erin Burns; Jacqueline Katz; Daniel Jernigan; Lynnette Brammer
• Keywords: Adult; Adolescent; Influenza A Virus, H3N2 Subtype; Infant, Newborn; Infant; Pneumonia; Middle Aged; 3. Good health; Hospitalization; Influenza B virus; 03 medical and health sciences; Influenza A Virus, H1N1 Subtype; 0302 clinical medicine; Influenza Vaccines; Child, Preschool; Child Mortality; Drug Resistance, Viral; Infant Mortality; Influenza, Human; Outpatients; Humans; Child; Aged

During the 2015-16 influenza season (October 4, 2015-May 21, 2016) in the United States, influenza activity* was lower and peaked later compared with the previous three seasons (2012-13, 2013-14, and 2014-15). Activity remained low from October 2015 until late December 2015 and peaked in mid-March 2016. During the most recent 18 influenza seasons (including this season), only two other seasons have peaked in March (2011-12 and 2005-06). Overall influenza activity was moderate this season, with a lower percentage of outpatient visits for influenza-like illness (ILI),(†) lower hospitalization rates, and a lower percentage of deaths attributed to pneumonia and influenza (P&I) compared with the preceding three seasons. Influenza A(H1N1)pdm09 viruses predominated overall, but influenza A(H3N2) viruses were more commonly identified from October to early December, and influenza B viruses were more commonly identified from mid-April through mid-May. The majority of viruses characterized this season were antigenically similar to the reference viruses representing the recommended components of the 2015-16 Northern Hemisphere influenza vaccine (1). This report summarizes influenza activity in the United States during the 2015-16 influenza season (October 4, 2015-May 21, 2016)(§) and reports the vaccine virus components recommended for the 2016-17 Northern Hemisphere influenza vaccines.