When Is It Too Late to Get a Flu Shot?
Key takeaways:
The best time to get a flu shot is right before flu season starts. Flu season usually starts by the end of October.
The flu shot is safe, effective, and recommended for most people.
The flu shot protects you even if you’ve already had the flu. So it’s almost never “too late” to get a flu shot.
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As the colder seasons approach, many people start preparing for fall and winter routines. For most people, this should include getting a yearly flu shot. The flu vaccine is effective and safe and provides protection against flu illness — both for you and for those around you.
Getting a flu vaccine can keep you from missing work or school due to illness. The flu vaccine also protects you against severe symptoms, which could require hospitalization. And the flu vaccine can be lifesaving for people at greater risk, including pregnant women, older adults, children, and people with chronic medical conditions.
But what if it’s already flu season, or if you’ve already had the flu? Is it ever too late to get the flu shot?
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When is the best time to get a flu shot?
The best time to get a flu shot is right before flu season begins, which usually means in September or October.
In most areas of the U.S., flu season is from October through May. Peak activity is usually from December through February.
The CDC recommends people get their flu shot by the end of October. It takes 2 weeks for your immune system to fully respond to a vaccine. So, it’s important to plan accordingly and get the vaccine before flu activity increases in your community.
Early vaccination — that is, getting a flu shot in July or August — is sometimes an option. This can make sense for young children who need 2 doses of the flu vaccine in the same year. You may also benefit from early vaccination if you’re pregnant or close to delivery.
But, in general, most people shouldn’t get vaccinated early. The flu shot gets less effective over time, so it works best if you wait until closer to flu season.
Should you get a flu shot if you’ve already had the flu?
Yes. Every year, several strains of flu spread through communities. Immunity to one strain of flu doesn’t protect you against other strains.
When is flu season? In the U.S., flu season generally goes from October through May. Learn more about timing your flu vaccine for maximum protection.
Do you really need the flu shot every year? Yes, flu strains are always changing, so getting the updated yearly flu shot is your best chance of avoiding infection.
Getting tested for the flu: The flu shot provides important protection, but it isn’t perfect. Here’s where to get tested for the flu.
That means you can get the flu more than once in a single year. The flu shot is designed to protect you against several of the most troublesome strains each season. So it makes sense to get vaccinated even if you’ve already recovered from the flu.
Where to get a flu shot
Flu vaccines are widely available during the flu season. There are many places you can go to get a flu shot, including:
Your doctor’s office
Most large chain retail pharmacies
Drive-thru flu-shot clinics
Pop-up flu-shot clinics at community centers and hospitals
Your local health department
There’s no “right” place to get the flu shot — you can go to any licensed healthcare professional offering a licensed flu vaccine. The CDC’s vaccine finder is a great resource to find vaccination sites in your area.
When not to get a flu shot
Nearly everyone should get a flu shot. However, the flu shot isn’t recommended for:
Anyone with a severe allergy or anaphylaxis to the flu vaccine or its ingredients
Infants younger than 6 months old
Anyone with a history of Guillain-Barré syndrome should talk with their healthcare team before getting a flu shot.
In rare situations, the risks of the flu shot can outweigh the benefits. In these cases, people need to talk with their healthcare team before getting a flu shot.
The flu shot is safe for people with egg allergies. Before 2023, people with egg allergies needed to take special precautions when getting a flu shot, but that’s no longer the case.
If you or your child is sick on the day of your flu shot appointment, make sure you let the healthcare professional know. Some people can still get vaccinated if they only have a minor illness. In some cases, they may recommend rescheduling the flu shot.
Is it too late to get a flu shot?
It’s almost never too late to get a flu shot. A flu shot will provide protection as long as the flu is circulating in the community. Since the flu circulates until late May in most parts of the U.S., even getting your shot in later winter or early spring will help keep you healthy.
Frequently asked questions
No, it's not too late to get a flu shot in January. In the U.S., the flu tends to stick around through May. You can even get the flu in the summer. So getting a flu shot in January still provides important protection.
Yes, you can get the flu shot pretty much any time of the year. But keep in mind that you’re more likely to have better protection if you get a flu vaccine right before the start of flu season, around September or October. Protection goes down over time, so the idea is to make sure you’re protected during the peak of flu season.
The bottom line
The best time to get a flu shot is 2 weeks before the flu season begins — usually by the end of October. But it’s really never too late to get a flu shot, as the virus is normally circulating in communities through May of each year. The flu vaccine can keep people safe from flu illness and be lifesaving for people who’re at risk for severe flu disease. The flu shot is recommended for nearly everyone older than 6 months old.
Why trust our experts?
References
Centers for Disease Control and Prevention. (2020). Who should NOT get vaccinated with these vaccines?
Centers for Disease Control and Prevention. (2023). Guillain-Barré Syndrome (GBS) and vaccines.
Centers for Disease Control and Prevention. (2024). Flu and children.
Centers for Disease Control and Prevention. (2024). Flu vaccines and people with egg allergies.
Centers for Disease Control and Prevention. (2024). Influenza vaccine safety considerations for people who are pregnant or breastfeeding.
Centers for Disease Control and Prevention. (2024). People at increased risk for flu complications.
Centers for Disease Control and Prevention. (2024). Weekly US map: Influenza summary update.
Centers for Disease Control and Prevention. (2024). Who needs a flu vaccine.
