Flu vaccine offered poor protection for seniors this year, CDC says

This season's influenza vaccine was largely ineffective for seniors, according to Centers for Disease Control and Prevention numbers released Thursday.

The flu vaccine was effective for only 9% of those 65 and older, as measured by a survey of nearly 2,700 adults and children undertaken between Dec. 3 and Jan. 19. This means the vaccine prevented a “statistically insignificant” number of seniors from needing outpatient medical attention for the flu, according to the CDC. Overall, the shot was 56% effective for all age groups over six months old.

Seniors generally are more severely affected by the flu and often are less responsive to vaccines than younger people. However, the flu-related death rate for seniors reached extremely high levels this year. The vaccine may have been ineffective because seniors did not respond to its influenza A (H3N2) component, the CDC stated. The vaccine was 67% effective in protecting seniors against influenza B.

The findings are interim, and the CDC plans further research to see if chronic medical conditions or other factors played a part in the vaccine's ineffectiveness among seniors. The flu shot's effectiveness has varied from year to year, so these findings should not be seen as discrediting the need for the vaccine, CDC officials stressed.