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Short answer: the CDC says everyone 6 months and older should get a flu shot every season, with rare exceptions. The best window is September and October, ideally finished by the end of October. If you have Medicare Part B, you pay nothing for the vaccine when your provider accepts assignment. Below is who needs what, based on the CDC and Medicare.gov.
Flu shot key facts for 2026-27
These details come from the CDC’s seasonal flu vaccine page, updated Sept. 1, 2026, and from Medicare.gov.
| Question | Answer |
|---|---|
| Who should get a flu shot? | Everyone 6 months and older, with rare exceptions |
| Best timing | September and October, ideally by the end of October |
| Protection starts | About two weeks after vaccination |
| Vaccine type this season | All U.S. flu vaccines are trivalent, meaning they cover three viruses |
| Medicare Part B cost | $0 if your provider accepts assignment |
When to get your flu shot
According to the CDC, antibodies take about two weeks to develop. So it is best to get vaccinated before flu spreads in your community. September and October are generally good months. Most adults, including those 65 and older, should avoid vaccination in July or August, because protection may wane. The same goes for pregnant people in their first or second trimester. If you haven’t had your flu shot yet, this is the week the CDC’s timing guidance points to. Getting vaccinated later is still better than skipping it.
Some children need two doses, at least four weeks apart. They should get the first dose as soon as vaccine is available. The CDC page does not give an age cutoff, so ask your child’s doctor whether two doses apply.
Which flu shot to choose
All U.S. flu vaccines this season are trivalent. They cover two influenza A viruses and one influenza B virus. For people under 65, the CDC does not prefer any age-appropriate vaccine over another. Options include the standard shot, recombinant vaccines, and the nasal spray. The nasal spray, FluMist, is approved for ages 2 through 49. It is not recommended for pregnant people, immunocompromised people, or people with certain medical conditions.
For people 65 and older, the CDC preferentially recommends three vaccines: Fluzone High-Dose, Flublok, and Fluad. If none is available, any other age-appropriate vaccine is acceptable. So don’t skip your flu shot to wait for a specific brand. People with an egg allergy may receive any flu vaccine that suits their age and health. Egg-free options include Flucelvax and Flublok.
What a flu shot costs with Medicare
Medicare.gov says Part B covers the seasonal flu vaccine as a preventive service. You pay nothing if your doctor or other provider accepts assignment. Medicare usually covers one vaccine each flu season. Other insurance, what your provider charges, and the type of facility can affect what you owe, so confirm before you go. You can get the vaccine at many places, including your doctor’s office and local pharmacy. Medicare points to vaccines.gov to find one. Our Medicare open enrollment guide covers the other coverage decisions due by Dec. 7. Our report on Medicare scams explains why you should never give your Medicare number to a caller offering a free flu shot.
What to expect afterward
The CDC says side effects are usually mild and short-lived. They include soreness, redness, or swelling where the shot was given, and sometimes headache, fever, muscle aches, nausea, or fatigue. The nasal spray can cause a runny nose, headache, and cough or sore throat in adults. Serious reactions are very rare. Vaccinated people can still get sick. But the CDC says vaccination is linked to milder illness and a lower risk of ICU admission and death. Effectiveness varies by season, age, health, and how well the vaccine matches circulating viruses.
If you are unsure which vaccine fits you, or you have a condition that affects your options, talk to your doctor or pharmacist. This guide is general information, not medical advice.
Editor’s take
Pick the flu shot you can get this week over the perfect one you can get next month. The CDC’s own guidance says any age-appropriate vaccine is acceptable if the preferred one is not available, and the end-of-October target is close. For Medicare members, the cost is $0 at a provider that accepts assignment. So cost should not be the reason to wait.
