Influenza Activity — United States, 2014–15 Season and Composition of the 2015–16 Influenza Vaccine

During the 2014-15 influenza season in the United States, influenza activity increased through late November and December before peaking in late December. Influenza A (H3N2) viruses predominated, and the prevalence of influenza B viruses increased late in the season. This influenza season, similar to previous influenza A (H3N2)-predominant seasons, was moderately severe with overall high levels of outpatient illness and influenza-associated hospitalization, especially for adults aged ≥65 years. The majority of circulating influenza A (H3N2) viruses were different from the influenza A (H3N2) component of the 2014-15 Northern Hemisphere seasonal vaccines, and the predominance of these drifted viruses resulted in reduced vaccine effectiveness. This report summarizes influenza activity in the United States during the 2014-15 influenza season (September 28, 2014-May 23, 2015) and reports the recommendations for the components of the 2015-16 Northern Hemisphere influenza vaccine.

[1]  Keiji Fukuda,et al.  Influenza-associated hospitalizations in the United States. , 2004, JAMA.

[2]  L. Brammer,et al.  Update: Influenza Activity — United States, September 28–December 6, 2014 , 2014, MMWR. Morbidity and mortality weekly report.

[3]  L. Brammer,et al.  Human infections with influenza A(H3N2) variant virus in the United States, 2011-2012. , 2013, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[4]  Erin Burns,et al.  Estimates of deaths associated with seasonal influenza --- United States, 1976-2007. , 2010, MMWR. Morbidity and mortality weekly report.

[5]  G. Gao,et al.  H7N9: a low pathogenic avian influenza A virus infecting humans , 2014, Current Opinion in Virology.

[6]  Richard K. Zimmerman,et al.  Early Estimates of Seasonal Influenza Vaccine Effectiveness — United States, January 2015 , 2015, MMWR. Morbidity and mortality weekly report.

[7]  Update: influenza activity--United States. , 1986, MMWR. Morbidity and mortality weekly report.

[8]  L. Gubareva,et al.  Antiviral agents for the treatment and chemoprophylaxis of influenza --- recommendations of the Advisory Committee on Immunization Practices (ACIP). , 2011, MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports.

[9]  E. Blumberg.  CDC Health Advisory Regarding the Potential for Circulation of Drifted Influenza A (H3N2) Viruses , 2015 .

[10]  L. Brammer,et al.  Update: Influenza Activity — United States, September 29, 2013–February 8, 2014 , 2014, MMWR. Morbidity and mortality weekly report.

[11]  L. Brammer,et al.  Outbreak of Variant Influenza A(H3N2) Virus in the United States , 2013, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[12]  L. Brammer,et al.  Update: Influenza activity--United States, September 28, 2014-February 21, 2015. , 2015, MMWR. Morbidity and mortality weekly report.