MMWR provides overview of 2013-14 influenza season, no change in flu shot composition

ATLANTA — A report published Friday in the Morbidity and Mortality Weekly Report characterized the 2013-2014 influenza season as the first season since 2009 that H1N1 generated fewer levels of outpatient illness and mortality as compared with seasons when influenza A (H3N2) is predominant. 

However, there were higher rates of hospitalization among adults ages 50 years to 64 years as compared to recent years, the report added. 

For next season, the Food and Drug Administration's Vaccines and Related Biological Products Advisory Committee has determined that the 2014–15 influenza vaccines used in the United States have the same antigenic composition as those used in 2013–14. The trivalent vaccines should contain an A/California/7/2009-like (2009 H1N1) virus, an A/Texas/50/2012-like (H3N2) virus and a B/Massachusetts/2/2012-like (B/Yamagata lineage) virus. The committee also recommended that quadrivalent vaccines contain a B/Brisbane/60/2008-like (B/Victoria lineage) virus.