MEDFORD, Ore. -- A newer version of the flu shot didn't have that much improvement as it worked slightly better for senior citizens last year with 24 percent effectiveness.
The best performance of the vaccine was a new shot called Flucelvax, which helped 26 and a half percent of seniors.
Flucelvax is made by growing viruses in animal cells, however, many of the other flu vaccines are made from chicken eggs.
The U.S. recently went through a flu season that sent more people to the hospital and killed more people especially seniors.
The FDA found that the chicken egg vaccines don't work well against that kind of flu bug.