CDC says flu shots might not be effective

The CDC is sending an advisory to doctors and clinicians, warning them that 52 percent of flu samples were not a good match for the current vaccine.

Making matters worse, H3N2, this year's strand, is especially bad, says ABC Chief Medical Correspondent Dr. Richard Besser.

“The H3N2 strain that's in the community this year tends to one that leads to more hospitalizations, much more severe than some of the other strains.”

According to the CDC, the virus has mutated or drifted, making the flu vaccine less effective, and it is too late to make any adjustments to the vaccine.

Those at highest risk are children under the age of two, people over 65, and people with heart or lung disease.

Doctors are being told to put those groups of people on anti-viral medications if they show any symptoms of the flu.

“I think this is a year where people have to take extra care. You want to wash your hands regularly. You want to make sure you are covering coughs and sneezes,” says Dr. Besser.

In a good year, the flu vaccine is only effective in about 60 percent of cases, and while this year it is especially bad, the CDC is still urging everyone to get the vaccine.