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The cumulative effect of annual flu shots

You hear it every year – “get your flu shot.”

And while of course it comes with a promise to protect against the strains of the current season, did you know it also can help years down the line?

The phenomenon is known as “cumulative immunity” and it’s the theory that individuals who receive a flu shot every year have a leg up when facing or battling new strains of the virus that might not be accounted for in the immunizations for the current season.

“We know someone like me who has had maybe 20 or more flu shots in their lifetime has more immunity than someone who has only had one or two inconsistently,” says Dr. Manuela Murray, a professor and provider with the UTMB Department of Pediatrics.

Dr. Murray, who says she has received a flu shot every year they’ve been available to her, not only understands the science behind the cumulative effect, but also experienced it working first hand many years ago.

“In 2009 when everyone was getting sick with the H1N1 strain of the flu during the Swine flu pandemic, I was working in the middle of urgent care seeing really sick patients around the clock –all while pregnant – and I never got sick,” says Murray. “I had all the markers to make me vulnerable to catch the illness but I stayed well and I attribute that to the many flu shots I had prior to that specific season.”

That might seem like a small, minor win, but when you think of how it helped protect not just Murray but her unborn babies (she was pregnant with twins!), too, during a time that was very uncertain to many, it’s a win that had a compounded, ripple effect.

Following this theory, it’s almost as if each flu shot you receive is an investment in the health of future you.

In this region, flu season typically runs from October through March, so to ensure the best protection for you and your loved ones throughout the current season, doctors and clinicians recommend getting the vaccination by the end of October.


More information on flu shots and the virus itself it available on this page.

View Dr. Manuela Murray's profile

Dr. Manuela Murray serves as the medical director of Ambulatory Operations for the Department of Pediatrics, including their Urgent Care. She strives to make sure every patient and parent leaves the clinic with all their concerns addressed and questions answered.

UTMB Health Pediatric Primary Care, Bay Colony

On my bio at the bottom of the article please change to something like "Dr. Manuela Murray serves as t erves as the director of Ambulatory Operations for the Department of Pediatrics, including their Urgent care