CDC: Flu bug may bite vaccines this year

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Steven E. Frischling/Bloomberg

The flu season may be more severe because the current vaccine isn't matching the strains that are active this year, which may put more people in danger, the Centers for Disease Control and Prevention warns.

Bloomberg reports that the most-active strain this year has been linked to more severe flu seasons. About half that strain's mutations make them different from those this year's vaccine targeted.

"The good news is that 50 percent match what's in the vaccine, and the bad news is 50 percent don't," Dr. Donald Kennedy, an infectious disease professor at St. Louis University, told the St. Louis Post-Dispatch.

Health officials must guess — well before the flu season starts — which strain the vaccine should target, Bloomberg reports. In good years, the effectiveness rate is 50 to 70 percent among adults younger than 65.

Despite the mismatch this year, health officials still say people's best bet is to get the vaccination, Bloomberg reports.