Everyone 6 months and older should get a flu shot every year. That’s the straightforward recommendation from the CDC, and it applies regardless of age, health status, or lifestyle. There are only a handful of exceptions, and most people don’t fall into them.
That said, the flu hits some groups harder than others. If you or someone in your household falls into a high-risk category, vaccination is especially important.
Who Is at Highest Risk for Flu Complications
While the flu vaccine is recommended for nearly everyone, certain groups face a much greater chance of serious illness, hospitalization, or death from influenza. For these people, getting vaccinated isn’t just a good idea; it’s a critical layer of protection.
Adults 65 and older and children younger than 2 are at the top of the list. Beyond age, a wide range of chronic conditions increase your risk:
- Lung conditions like asthma, COPD, and cystic fibrosis
- Heart disease, including congestive heart failure and coronary artery disease
- Diabetes and other endocrine disorders
- Kidney or liver disease
- Blood disorders like sickle cell disease
- Neurologic conditions, especially those affecting muscle function, swallowing, or the ability to clear the airways
- Weakened immune systems from conditions like HIV or cancer, or from treatments like chemotherapy, radiation, or long-term corticosteroids
- Obesity with a BMI of 40 or higher
- History of stroke
People younger than 19 who take long-term aspirin-containing medications are also at elevated risk because of a rare but serious condition called Reye’s syndrome, which can develop when aspirin use overlaps with a viral infection like the flu.
Flu Shots During Pregnancy
If you’re pregnant, the flu vaccine is safe during any trimester, and it does double duty. Your body produces antibodies after vaccination that cross the placenta and reach your baby, providing protection during the first several months of life before the baby is old enough to be vaccinated. If you’re breastfeeding, those antibodies also pass through breast milk.
If you’re in your third trimester and vaccine is already available in July or August, getting vaccinated early can maximize the protection your newborn receives during those vulnerable first weeks. One important note: pregnant individuals should get the injectable flu shot, not the nasal spray version.
What Parents Need to Know
Children can receive their first flu vaccine at 6 months old. For kids between 6 months and 8 years old, the number of doses matters. If your child is getting a flu vaccine for the first time, has only ever received one dose in a previous season, or has an unknown vaccination history, they need two doses this season, spaced at least four weeks apart. That means starting early. Getting the first dose as soon as vaccine becomes available gives enough time to complete the series before flu activity picks up.
Children who have been fully vaccinated in at least one previous season only need a single dose going forward.
Stronger Vaccines for Adults 65 and Older
Aging weakens the immune response to standard flu vaccines, so the CDC preferentially recommends that adults 65 and older receive one of three enhanced vaccine options: a high-dose version, a recombinant version, or an adjuvanted version. These formulations are designed to provoke a stronger immune response. Studies suggest they are more effective in this age group than the standard-dose shot.
If you’re 65 or older and your pharmacy or clinic only has the standard vaccine available, getting that is still better than skipping vaccination entirely. But if you have the choice, ask for one of the enhanced options.
Protecting People Around You
Some of the most vulnerable people can’t be vaccinated at all. Babies under 6 months are too young. Some people with severely weakened immune systems may not mount a strong response even after vaccination. If you live with, care for, or spend time around anyone in these categories, your flu shot is their shield. The more vaccinated people surrounding a vulnerable person, the lower the chance the virus reaches them.
Egg Allergies Are No Longer a Barrier
For years, people with egg allergies were told to take extra precautions before getting a flu shot, since most flu vaccines are manufactured using eggs. That guidance has changed. Starting with the 2023-2024 season, people with egg allergies can receive any flu vaccine appropriate for their age, regardless of how severe their egg allergy has been in the past. No additional safety measures beyond what’s standard for any vaccination are needed. Egg-free vaccine options also exist if you prefer them.
Who Should Not Get a Flu Shot
The list of people who truly cannot receive a flu vaccine is short. Babies younger than 6 months are too young. Anyone who has had a severe, life-threatening allergic reaction to a previous dose of flu vaccine should not receive that same vaccine again, though they may be able to get a different formulation. People with severe allergies to any vaccine ingredient other than egg proteins (such as gelatin or certain antibiotics) should avoid vaccines containing those ingredients.
If you’ve ever had Guillain-Barré syndrome, a rare condition that causes temporary paralysis, talk with your doctor before getting vaccinated. Some people with a history of this condition should skip the flu shot, but this is evaluated on a case-by-case basis.
When to Get Vaccinated
September and October are the sweet spot for most people. It takes about two weeks after vaccination for your body to build up protective antibodies, so getting your shot by the end of October means you’re covered before flu season typically peaks. If you miss that window, getting vaccinated later in the season still offers protection, especially since flu activity can last into spring.
The one exception to the September-October guidance is pregnant individuals in their third trimester, who may benefit from earlier vaccination in July or August when vaccine first becomes available, to pass along the most antibodies to their baby before delivery.