CDC: 2014-2015 Flu Vaccine Only 23% Effective

This year’s seasonal flu vaccine is only 23% effective against the predominant circulating virus strains, according to a recent CDC report.

In a study of the vaccines effectiveness, CDC researchers analyzed 2321 patients with acute respiratory illness who sought outpatient care throughout 5 US states between November 10, 2014 and January 2, 2015.
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The researchers discovered that overall, 41% of individuals tested positive for the influenza virus. Further, the CDC reported that while 96% (916) of the viruses were influenza A (H3N2)—and 33% were antigentically similar to influenza A—68%(16) of the viruses varied antigenically from those in the vaccine.

Despite these results, the CDC still urges individuals to be vaccinated if they have not already done so, as the vaccine is still effective in preventing some influenza A and B infections, and complications associated with the illness.

“These early vaccine effectiveness estimates underscore the need for additional influenza prevention and treatment measures, especially among persons aged ≥65 years, young children, and other persons at higher risk for serious influenza associated complications,” they concluded.

-Michelle Canales

Reference:

Flannery B, Clippard J, Zimmerman RK, et al. Early estimates of seasonal influenza vaccine effectiveness—United States, January 2015. MMWR. 2015;64(01):10-15.