Flu vaccine is not current to the flu strain circulating

(KYMA, KECY) - There's concern that this year's flu shot may not be effective against the most common strain of influenza that is circulating.

In an outbreak at the University of Michigan last month that affected more than 700 people, more than 26% who tested positive had already received flu shots.

Researchers believe that may mean the current flu vaccines don't match the most common viruses this year.

They point out that while the vaccine may not protect as many people from the flu, it should still reduce the risk of hospitalizations and deaths.

CDC scientists have said influenza virtually disappeared last year, but it is expected to return with a vengeance.