But a new study is raising doubts about this year's flu shot.
Flu season has arrived early to North America this year, and it may end up being a doozy.
The Indianapolis Colts and the Indiana State Department of Health (ISDH) are teaming up for a fourth season to help Hoosiers beat influenza (flu). The Centers for Disease Control's effectiveness studies measure laboratory-confirmed flu illnesses that result in a doctor's visit or those that result in hospitalization.
When news starts circulating that the flu shot may not work, some people skip it. Sweeney said that's the wrong choice.
"I think that the key preventative strategy, regardless of how effective that vaccine is going to be this year in the United States, is to get vaccinated", says Dr. Lopez.
Cases of flu tend to ramp up mid- to late-December and peak in January or February, according to Paul Sax, an infectious disease physician at Brigham and Women's Hospital in Boston.
The Journal noted that another factor in the vaccine's ineffectiveness this year is the way it's made, using eggs to grow the strains.
This season, only injectable flu vaccines are recommended. Experts worry because the H3N2 portion of the vaccine used here in the U.S.is identical to the one used in Australia.
"Based on what is in the vaccine versus a genetic analysis of strains that have been isolated, there is a ideal match", Venglarcik said.
But that doesn't mean you shouldn't go out and get your flu vaccine, Hirsch cautions.
"We're still seeing colds from the fall season but we're beginning to see sporadic flu activity in the community", said Dr. Chris Cunha, a pediatric doctor in Northern Kentucky.