Get a Flu Shot Now or Wait?

Experts are recommending Americans get vaccinated in September or October in case flu season comes early again this year.

Medically Reviewed
It’s better to get a flu vaccine before infection rates climb in your community.

If you typically wait until your Thanksgiving turkey is thawing before scheduling a flu shot, you may want to rethink your vaccination game plan for this year.

Last year’s flu season peaked early, with an unusually high number of cases in September, which could mean we’re more likely to have an early flu season this year, too.

Experts often look at flu rates in the Southern Hemisphere to project what the season might be like in the United States, says Tia Babu, MD, an infectious disease specialist at UW Medicine in Seattle.

“According to data submitted to the World Health Organization (WHO), there’s been high flu activity for this time of year in South Africa, while Australia has been having typical levels. Mexico, while not in the Southern Hemisphere, is seeing abnormally high flu activity in May and June, which isn’t the norm,” says Dr. Babu. “While not a perfect prediction, this all suggests we could have a significant flu season in the U.S. this year.”

The best thing you can do to protect yourself is to get a flu vaccine once it’s available, she says.

Have questions about timing, safety, or side effects? Here are answers to a few common questions about getting the flu vaccine.

When’s the Best Time to Get a Flu Shot?

“I typically recommend that people get their flu shot in September or October,” says Babu.

But timing takes a back seat if it’s a choice between getting vaccinated a little early or not at all, she says. “The most important thing is to get the flu shot so that you’ll be protected.”

If You Get the Flu Shot Too Early, Can It Wear Off Before Flu Season Is Over?

There is some truth to the concept that the flu shot can lose its effectiveness over time, says Frederick Chen, MD, MPH, chief of family medicine at Harborview Medical Center and professor of family medicine at the University of Washington School of Medicine in Seattle. “In general, we don’t recommend people getting the flu shot in July or August,” he adds. “It’s a good idea to wait until the middle of September.”

There are a few exceptions to the rule, per the Centers for Disease Control and Prevention (CDC):

  • Pregnant women in their third trimester can get a flu shot in July or August to ensure that their babies are protected after birth.
  • Children who need two doses of the flu vaccine should get their first dose as soon as it becomes available, with the second dose given at least four weeks later.
  • Vaccination in July or August can be considered for children who have back-to-school doctor appointments and might not return to see a healthcare provider in September or October.

There’s Hardly Any Flu in My Area Right Now. Can I Wait to Get My Flu Shot?

It’s best to be vaccinated before flu begins spreading in your community, per the CDC. Not only is it difficult to predict the timing of flu activity, keep in mind it takes about two weeks for the vaccine to take full effect, according to Mayo Clinic.

While there may not be any cases of flu in your area right now, the virus can start spreading at any time. Ideally, you should get vaccinated against flu by the end of October so you’re protected once the flu arrives in your community, according to the CDC.

Is It Ever Too Late to Get the Flu Shot?

It’s never too late to get a flu shot, says Dr. Chen. As long as flu viruses are still circulating, it’s still worth getting a flu shot, even if it’s February or March.

“Especially this year, you should get a flu shot as soon as you can. 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 Shot Be?

Each year, an advisory committee to the U.S. Food and Drug Administration (FDA) reviews and updates the composition of U.S. flu vaccines to best match the viral strains predicted to be the most common during the upcoming season, according to the CDC.

How well the flu vaccine works can depend on the accuracy of this match. It’s estimated that last season, people who were vaccinated against the flu were about 40 to 70 percent less likely to be hospitalized because of flu illness or related complications, per the CDC.

Can I Get My Flu Shot and a COVID-19 Vaccine in the Same Visit?

Yes, people can now receive a COVID-19 vaccine (including a booster shot, if and when you’re eligible) and the flu shot during the same visit, says the CDC.

Although getting the vaccines at the same time won’t change their efficacy, adding the flu shot to your COVID booster may make you more likely to experience side effects including fatigue, headache, and muscle aches, according to a study published July 2022 in JAMA Network Open.

What Are the Most Common Side Effects of the Flu Shot?

A sore arm and redness where the vaccine was given, headache, fever, nausea, muscle aches, and fatigue are the most common flu shot side effects, according to the CDC. These are generally mild and go away on their own within a day or two.

Can I Get a Flu Shot and RSV Vaccine in the Same Visit?

The CDC recommends adults 60 and older get the RSV (respiratory syncytial virus) vaccine (after a discussion with their doctor) to help prevent potentially serious complications from this common virus. It is safe to get the RSV vaccine at the same time as other vaccines, including the flu shot.

Should I Be Worried About a Flu Shot Shortage?

The flu shot is produced by private manufacturers, and so supply depends on those companies. Those manufacturers have projected that they will provide the United States with as many as 170 million doses of flu vaccines, states the CDC — about the same amount of shots that were distributed last year.

Is It Really Okay to Get a Flu Shot at a Pharmacy or Grocery Store Instead of a Doctor’s Office?

Yes, it’s perfectly safe to get your flu shot at your local pharmacy or grocery store, provided the workers and nearby patrons are following COVID-19 safety guidelines, says Chen.

The online directory VaccineFinder can show you locations in your area that offer flu shots. Note that flu shots are free with most insurance.

Should Anyone Not Get a Flu Shot?

According to the CDC, virtually everyone should get a flu shot. The only exceptions:

  • Children under 6 months old should not get the flu shot.
  • People who have severe, life-threatening allergies to the flu vaccine or any ingredients in the vaccine should not get the shot. This may include gelatin, antibiotics, or other ingredients. Severe allergic reactions to flu vaccines are very rare.
  • Some people who have had a rare disorder called Guillain-Barré syndrome (GBS) should not get a flu vaccine and should discuss their situation with a doctor.

The CDC has announced a change this year related to recommendations for flu vaccines for people with egg allergies.

Most flu vaccines today continue to be produced using an egg-based manufacturing process and contain a small amount of egg proteins, such as ovalbumin, according to the CDC.

Unlike in previous years, the CDC now says it’s safe for for people with egg allergies to receive any flu vaccine — egg-based or non-egg-based — that is appropriate for their age and health status. Additional safety measures are no longer advised, according to the CDC.

Is It True That Getting a Flu Shot Can Give You the Flu?

Most years only about half of Americans get flu shots, notes Chen. “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,” he says. “Let me be clear: Flu shots do not give you the flu.”

There are a few reasons why someone might feel like they’ve gotten sick because of the shot. “Some people may experience flu symptoms after being vaccinated because they become ill from different respiratory viruses such as rhinoviruses, which are associated with the common cold,” he says.

It’s also possible to become ill with the flu shortly after being vaccinated because it takes up to two weeks for the body to develop immune protection after the shot, notes the CDC.

If you have any concerns or hesitation about getting the flu shot, talk to your healthcare provider, says Babu.

Flu vaccines do vary in how well they work, so people who are vaccinated can still get sick. But even if that happens, research shows that the vaccine can still help by reducing flu severity.

A study published in June 2021 in Vaccine found that in adults hospitalized due to the flu, those who were vaccinated had a 26 percent lower risk of ICU admission and a 31 percent lower risk of death compared with those who were unvaccinated.

The vaccine can be lifesaving in children, too: The flu shot reduced children’s risk of severe life-threatening influenza by 75 percent, according to a study published in July 2022 in Clinical Infectious Diseases.