Answers to Other Flu Shot FAQs
Find out more about the flu shot, including side effects, whether it can make you sick, how effective it is, and whether it’s okay to get your flu shot and other vaccines at the same time.
Can I Wait to See if There’s Lots of Flu Where I Live Before Getting Vaccinated?
Trying to sync your flu shot with flu activity in your area is not only difficult but also may also leave you vulnerable. The virus can start spreading at any time, and that can be hard to predict.
Keep in mind that it takes about two weeks for the vaccine to take full effect.
Is It Ever Too Late to Get the Flu Vaccine?
It’s never too late to get a flu shot, Chen says. As long as flu viruses are still circulating, it’s still worth getting vaccinated, even if it’s February or March.
“It’s recommended that you get the flu shot in the fall, but if for some reason you wait until later in the season, you should still get it,” he adds.
How Effective Will This Year’s Flu Vaccine Be?
Each year, an advisory committee to the U.S. Food and Drug Administration reviews and updates the composition of U.S. flu vaccines to best match the viral strains expected to be the most common during the upcoming season.
The vaccine’s effectiveness depends on the accuracy of this match, and it’s too early to know exactly how good this year’s prediction will be.
For the 2025–26 season, the vaccine was 30 percent effective in preventing flu-related hospitalizations in adults and 41 percent effective in preventing flu-related hospitalizations in children.
A standard flu vaccine protects against three viral strains. This year, all three virus components have been updated from the 2025–2026 vaccine. This should enhance protection against variations including influenza A (H1N1, or swine flu), influenza A (H3N2) subclade K, and influenza B (Victoria lineage), which circulated widely during last year’s flu season.
“Despite not being perfect, the data show that vaccination is one of the best ways to protect yourself against seasonal influenza,” says Tony Moody, MD, professor of pediatrics and infectious diseases at Duke University School of Medicine in Durham, North Carolina, and director of the Duke CIVICs Vaccine Center.
Can I Get a Flu and COVID-19 Vaccine at the Same Time?
Although getting multiple vaccines at the same time won’t change their efficacy, you might be more likely to experience side effects.
What Are the Most Common Side Effects of the Flu Shot?
Should I Be Worried About a Flu Vaccine Shortage?
The flu vaccine is produced by private manufacturers, and so the supply depends on those companies. Those manufacturers have projected that they will provide the United States with an adequate supply of vaccines for the 2026–27 season.
Currently, there are no delays, and the vaccine is already available.
Is It Really Okay to Get a Flu Shot at a Pharmacy or Grocery Store?
Yes, it’s perfectly safe to get your flu shot at your local pharmacy or grocery store, Chen says.
The online directory VaccineFinder can show you locations in your area that offer flu vaccines. Note that these are free with most insurance.
Is the Flu Season Expected to Be Bad This Year?
Experts often look at flu rates in the Southern Hemisphere to project what the season might be like in the United States.
That data suggests that the flu will continue to pose a significant threat, causing many illnesses, hospitalizations, and deaths across the globe.
The Southern Hemisphere influenza season is still underway but has been relatively mild, compared with historical averages, and influenza A vaccine coverage has been good, says Michael Ben-Aderet, MD, medical director of hospital epidemiology at Huntington Health, a Cedars-Sinai affiliate in Pasadena, California. That suggests that the flu season in the Northern Hemisphere could be milder than the past few years, though it’s not a guarantee.
“Even in a lighter season, flu is a serious illness for those who get it, and vaccination remains the best protection,” Dr. Ben-Aderet says.
Is It True That Getting a Flu Shot Can Give You the Flu?
“The most common reason that I hear about why people don’t want a flu shot is that they got a flu shot once and got the flu afterward,” Chen says. Most years, only about half of Americans get flu shots, he says.
Fewer than 42 percent of adults and around 50 percent of children received flu vaccines in the 2024–2025 season — the most recent season for which data is available.
“Let me be clear: Flu shots do not give you the flu,” Chen notes.
The shot uses an inactivated version or single protein of the flu virus, and it cannot transmit illness. If you get sick shortly after having the shot, it’s likely because you were exposed to the flu or another upper respiratory illness (such as COVID-19 or RSV) in the week or so before your shot.
Flu vaccines do vary in how well they work, so people who are vaccinated can still get sick during the flu season. But even if that happens, the vaccine can still help by reducing flu severity.
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