CDC: Seasonal Flu Vaccine Only 18% Effective
According to health officials, this year’s flu vaccine was only 18% effective against the dominant H3N2 strain of flu, even lower than the 23% protection estimated earlier in the season.
Even worse, the CDC panel reported 15% effectiveness for children between the ages of 2 to 8 for the injected vaccine.
Researchers attributed the low percentages to the fact that circulating flu viruses have mutated and appear differently than the vaccine strains as a result. The current strain of H3N2 manifested for the first time in March 2014, a month after the vaccine had been created.
Since the flu season has not yet ended, the CDC still recommended a flu vaccination for ages 6 months and older. The health officials noted that an increasing number of B viruses are currently circulating which are a closer match to the vaccine and could raise the final vaccine effectiveness percentage up.
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“Year in and year out, flu vaccines are still the best way to protect yourself against flu. Most years, the vaccine is 50% to 70% effective. The vaccine doesn't protect everybody every time, but its odds on the best way to protect yourself against flu,” said Joseph Bresee, MD, the chief of Epidemiology and Prevention branch at the CDC’s National Center for Immunization and Respiratory Disease.
The CDC further recommended treatment with antiviral drugs (eg, Tamiflu and Relenza), washing hands frequently, and covering mouths when sneezing or coughing as other methods to prevent the spreading of the flu virus.
The complete CDC recommendations are published on the National Institutes of Health’s website.
-Michelle Canales Butcher
Reference:
Medline Plus (National Institutes of Health). Seasonal flu vaccine even less effective than thought: CDC. February 26, 2015. www.nlm.nih.gov. Accessed March 2, 2015.