This year's flu shot was only 36 percent effective overall, according to new government data. The findings were published by the Centers for Disease Control and Prevention as they are dealing with the worst flu season in a decade.

In a typical season, vaccines prevent 40% to 60% of flu cases serious enough to send people to the doctor. Most illnesses this Flu season have been caused by Type A H3N2. The vaccine was only 25 percent effective against that strain.

William Schaffner, M.D., Vanderbilt University says, "against the dominate strain, the H3N2 strain, we sure do wish the vaccine were more effective." But the good news is that it works better in kids. The vaccine provided 59 percent protection against H3N2 in children 8 and younger.

Dr Schaffner says this year's shot does offer more protection for other strains that are circulating. " Late in the influenza season is when these influenza B strains usually are more active and fortunately the vaccine is more effective against those strains, it's about 42 percent effective," says Schaffner.

With flu still circulating it makes sense to get vaccinated if you haven't already. Experts say they expect to see flu well into March. The vaccination, even though not as effective as hoped, can also reduce the severity of flu symptoms for people who do get sick.