, the CDC says on its website . NEW : Vaccine is about 90 % effective , CDC director says . But the flu vaccine is n't a guarantee that you will be healthy . The most common flu infection this year is a match with the vaccine . But even if it does n't stop illness , it can stop some disease , Dr. Bill Schaffner says .
NEW : Vaccine is about 90 % effective , CDC director says . But the flu vaccine is n't a guarantee that you will be healthy . The most common flu infection this year is a match with the vaccine . But even if it does n't stop illness , it can stop some disease , Dr. Bill Schaffner says .