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Even though fall isn’t over, it’s not too early to think about the flu — and the flu shot.
A recent study indicates that getting vaccinated every year might not provide as much protection as people think: People who haven’t been vaccinated in the past five years seem to see the biggest immune boost from the vaccine. Still, experts urge people not to skip their vaccination — the flu vaccine protects people from three of the four strains of flu likely to hit this year.
Besides, the recent research seems to go against everything experts know about the flu shot. Getting one every year boosts your response to the older strains of the virus.
“Even if there is chance that what these studies found is true, that should not and would not ever translate into forgoing the flu shot yearly,” says Dr. Natalie Azar, NBC’s medical contributor.
In a 2014 paper, researchers at Marshfield Clinic Research Foundation and the Centers for Disease Control and Prevention looked at 7,315 people to determine whether they contracted the flu and if they had been vaccinated over the past five years. They found that the vaccine protects everyone from contracting the flu, but people who had not been vaccinated in the prior five years experienced more protection from the virus.
The researchers only looked at vaccines’ effect on one strain of the flu: H3N2, which is most prevalent this year.
“Researchers don’t understand why —if you receive the flu shot year after year — that your response is going to be dampened because of prior exposure,” says Azar. The researchers say the results indicate that more study needs to be done.
Over the years, the flu vaccines’ effectiveness has come into question, with some vaccines providing little protection. “In the time they are making the vaccine, the virus can mutate. That’s what happened last year,” Azar explains.
Still, the bottom line remains: Get a flu shot every year.
The CDC recommends that everyone older than 6 months receive a flu shot annually, unless they’ve experienced a reaction from it. The body’s immune response weakens over time, meaning that vaccine from two years ago is likely too weak to work. In addition, the virus changes constantly, and this year's vaccine is best able to protect against the latest strain.