There was a lot of talk last winter about how the flu vaccine had fallen short of expectations in terms of protecting people from getting sick. And it’s true that it wasn’t as effective as we’ve seen in previous years.
According to the CDC, the overall effectiveness of last year’s flu vaccine was 36% (compared to 56% the year before). “Last year wasn’t a great match,” admits Blake Arthurs, M.D., a family medicine physician at Henry Ford Health. “But it still helped save a lot of people from getting seriously ill and ending up in the hospital.”
How Effective Is This Season’s Flu Vaccine?
In any given year, the flu vaccine is about 40% to 60% effective—provided the vaccine and the circulating strains of flu are a good match. When it’s a mismatch (like it was last year), those statistics drop.
This year’s vaccine has been formulated to target what the World Health Organization predicts will be the three most commonly circulating strains. This year’s vaccine protects against one strain of influenza B and two of influenza A—including the H3N2 subclade K virus that struck so many people late last winter.
“It takes about six months to identify strains and produce a new vaccine,” explains Dr. Arthurs. “And since things can still mutate throughout the flu season, it’s too early to accurately predict exactly how effective this season’s vaccine will be.”
The Benefits of Getting Your Flu Shot Every Year
Medical experts stress that the best way to protect yourself from the flu is to get the updated shot every season. That’s partly because the benefits can be cumulative. “Each new flu shot you get helps your immune system recognize and fight the virus,” says Dr. Arthurs.
And even when the vaccine isn’t a perfect match, there are many good reasons to get the shot. Not everyone will be spared a case of the flu, but historically, getting the shot has saved millions from severe infection, hospitalization or even death.
The numbers speak for themselves. The CDC estimates that during the 2024-2025 flu season, the shot prevented:
- 10 million illnesses
- 5 million doctor visits
- 180,000 hospitalizations
- 12,000 deaths
What’s the Best Time to Get a Flu Shot?
Family Medicine At Henry Ford
“Ideally, you want to get your flu shot two to six weeks before you might be exposed to the virus,” says Dr. Arthurs. “Getting it in September or October gives your immune system time to ramp up protection before flu season kicks into high gear.”
Getting your shot in early fall will protect you throughout flu season. But getting it too soon (like in July or August) could leave you with waning protection come late winter.
If you forget to get your shot in the fall, it’s still worth rolling up your sleeve. Getting it later in the winter will still help protect you for the remainder of flu season.
Yes, You May Get the Flu Anyway
Unfortunately, you can get your flu shot and do everything you can to protect yourself and still end up sick. If that’s the case, you can do an over-the-counter influenza test or see your doctor to get tested. If it is the flu, your doctor may prescribe antiviral medication to help lessen the severity and help you recover sooner.
It’s important to note that the flu shot itself cannot give you the flu. “You may feel tired or feverish from your immune response to the vaccine, but typically only for a day or so,” says Dr. Arthurs. “And it’s reducing your risk of getting the flu and feeling that bad or worse for a week to ten days.”
Reviewed by Blake Arthurs, M.D., a family medicine physician who sees patients at Henry Ford Family Medicine – Beck Road and via telemedicine.
