Flu Vaccines for 2026–2027: What You Need to Know

The best way to protect yourself against serious flu illness is to get an annual flu vaccine.

Getting a flu vaccine doesn’t guarantee that you won’t come down with the flu: Flu viruses are constantly evolving (mutating), helping them evade vaccine protections. Sometimes the strains selected for the seasonal flu vaccine are a poor match to the circulating strains.

There are two main ways to get vaccinated against the flu: a shot or a nasal spray. Both teach your immune system to recognize influenza viruses so it can respond more quickly to a future exposure.

Which Flu Strains Will These 2026–2027 Vaccines Protect Against?

All U.S. flu vaccines for the 2026–2027 season will protect against three viruses, including two influenza A viruses and a B/Victoria-lineage virus.

Vaccination is especially important for people who are more likely to become seriously ill with influenza:

People With Chronic Medical Conditions Certain long-term health problems can increase the risk of serious flu complications, including asthma and other lung diseases, diabetes, heart disease, neurologic conditions, a history of stroke, metabolic disorders, and kidney, liver, or blood disease.

Virtually everyone should get an annual flu vaccine, major medical organizations say. The exceptions:

• Children younger than 6 months
• People who have life-threatening allergies to the flu vaccine or any of its components, including gelatin or antibiotics (extreme allergic reactions to flu vaccines are very rare)
• Some people who’ve had a rare nerve disorder called Guillain-Barré syndrome

Don’t skip vaccination because you missed the ideal time in the fall; flu can circulate well into winter and spring, and getting vaccinated later can still provide meaningful protection.

There are more choices this season, including the first mRNA flu vaccine.

Standard-Dose Flu Shots

Traditional inactivated flu vaccines are available for people starting at 6 months of age, although approved ages vary somewhat by vaccine.

Many standard flu vaccines are grown in chicken eggs. Cell-based vaccines such as Flucelvax are made using mammalian cells instead and are approved for people 6 months and older.

Recombinant Flu Vaccine

The New mRNA Flu Vaccine

“This is really significant,” says Paul Pottinger, MD, director of the infectious diseases and tropical medicine clinic at UW Medical Center in Seattle. “It gives us not only a new choice but also a more nimble, responsive way to help prevent flu.”

The mRNA flu vaccine, which uses the same technology as many COVID-19 vaccines, can be produced much faster than traditional vaccines, which could eventually allow manufacturers to use more recent information about circulating viruses and potentially reduce the chances of a mismatch between the vaccine and the flu strains that arrive later in the year, Pottinger says.

There isn’t currently a recommendation that people 50 and older wait for mFlusiva or choose it over another age-appropriate vaccine.

Higher-Dose and Adjuvanted (Boosted) Vaccines

Nasal Spray Flu Vaccine

The nasal spray flu vaccine is approved for people ages 2 through 49, except for those with certain conditions. You can get this vaccine at a doctor’s office, healthcare clinic, or pharmacy, or you can purchase it online to administer yourself — no prescription needed.

• Those who’ve had a severe allergic reaction to a flu vaccine in the past
• Pregnant people
• Young people who take aspirin or a salicylate-containing medicine
• People with weakened immune systems and those who are caregivers or close contacts of them
• Children between ages 2 and 4 years old diagnosed with asthma or wheezing in the past 12 months
• People who recently took antiviral medicine for the flu
• People with a cerebrospinal fluid leak or the potential for a leak, as with a cochlear implant

Some people also develop other minor symptoms, including:

• Low-grade fever
• Headache
• Achiness
• Fatigue
• Nausea

• Injection-site pain
• Fatigue and headache
• Muscle and joint pain
• Chills
• Nausea
• Fever

• Fever in children ages 2 to 6 years old
• Runny nose and nasal congestion in people ages 2 through 49 years old
• Sore throat in adults

Flu vaccines can cause rare complications, such as:

Guillain-Barré Syndrome Some studies have found a possible link between the flu shot and Guillain-Barré syndrome, a progressive nerve disorder that can cause profound weakness for weeks or longer. Overall, studies estimate the prevalence of Guillain-Barré as fewer than 1 or 2 cases per million people vaccinated.

Although most infectious disease specialists agree that thimerosal, a vaccine preservative, poses no health risk and has a strong safety record, flu vaccines no longer contain this ingredient.

This is because the Advisory Committee on Immunization Practices (which issues recommendations to the CDC) voted against recommending flu shots containing this ingredient for the 2025–2026 season.

There are a few reasons why someone might feel like they’ve gotten sick because of getting vaccinated:

Vaccine Side Effects Some people have muscle aches and a fever for a day or two after receiving a flu vaccine. This may be a side effect of your body’s production of protective antibodies.

The Two-Week Window It takes about two weeks for the flu shot to take full effect, so if you’re exposed to the influenza virus shortly before or during that time period, you might catch the flu.

Flu vaccines are available at doctors’ offices, pharmacies, health clinics, urgent care centers, and most retail pharmacies.

Availability of the new mFlusiva mRNA flu vaccine may be more limited during its first season. If you’re due for your flu vaccine and another appropriate formulation is available, there’s no reason to delay vaccination solely to wait for mFlusiva, says Pottinger.