Key takeaways
- Get the flu shot every year to protect yourself and your community. The Centers for Disease Control and Prevention (CDC) recommends an annual flu vaccine for everyone aged 6 months and older with rare exceptions.
- Flu shots are safe and effective. The flu vaccine has been extensively studied and proven safe for more than 80 years. It reduces the risk of severe illness, hospitalization, and death.
- Aim to get your flu shot in September or October for protection during the entirety of flu season. This timing allows your body to build immunity before flu activity peaks, typically between the end of December and end of February.
- Get a flu vaccine near you at a location like a local pharmacy or primary care provider’s office. Pick one that’s most convenient for you. Some places may only offer the flu vaccine to patients of certain ages, or may not have the vaccines for patients 65 and older. Check in advance before you make an appointment.
The Centers for Disease Control and Prevention (CDC) recommends an annual flu vaccine for anyone aged 6 months or older, with rare exceptions. Each year, the flu causes millions of illnesses and medical visits, as well as thousands of hospitalizations and deaths. The flu vaccine reduces the risk of those outcomes. Not only does the flu shot protect you from getting sick, it also helps protect the people in your community.
“Patients who are older, pregnant, immunocompromised, and very young children are especially at risk of serious outcomes from the flu. By getting the flu vaccines, individuals can reduce their risk of severe illness should they get the flu, and protect those around them,” says Erica S. Shenoy, MD, PhD, chief of Infection Control at Mass General Brigham.
Learn more about when to get the flu shot to stay healthy this flu season and get answers to other common flu vaccine questions.
What is the best time to get a flu shot?
Flu season usually runs from October to May, with the season typically peaking between the end of December and end of February.
“The CDC recommends getting the flu vaccine in September or October to give you protection for the entirety of the flu season,” Dr. Shenoy explains. “During last season, 2025-2026, flu started ramping up in mid-November and peaked around the New Year.”
Once you get the flu vaccine, it takes your body about 2 weeks to build a complete immune response.
For kids, aged 6 months to 8 years, you need to plan ahead. That’s because kids in this age group may need 2 doses, 4 weeks apart, depending upon prior influenza vaccination.
“It can get a little complicated, so even though I’m an infectious diseases doctor, when I’m being ‘mom,’ I look up the latest recommendations each year,” says Dr. Shenoy.
To learn more about dosing for this age group, you can view the CDC's recommendations.
Is it too late to get a flu shot?
No. The flu can spread for many months and getting a flu shot later in the season still provides many benefits. It reduces the risk of severe illness, hospitalization, and death.
Flu shot efficacy
Annual flu shots are very effective and each year scientists reformulate them to provide protection against the most likely circulating strains of the virus. Some people who get the flu vaccine, but still come down with the flu, might think that the vaccine doesn’t work well.
“That’s actually not true,” says Dr. Shenoy. “Study after study has shown that people who get the vaccine and become infected with influenza have less severe disease. In fact, the effectiveness of the influenza vaccine during the 2025-2026 season was 36% . While the reported effectiveness was slightly lower than the last 2 years, this level of protection prevents tens of thousands of hospitalizations. In fact, in the 2022-2023 season, when vaccine effectiveness was 30%, an estimated 71,000 hospitalizations and more than 4,000 deaths were prevented by vaccination.
Chart shows the level of seasonal flu vaccine effectiveness from 2009-2010 through 2025-2026 flu seasons. *2020-2021 flu vaccine effectiveness wasn’t estimated due to low influenza virus circulation during the 2020-2021 flu season.†† Estimates for 2024-2025 and 2025-2026 flu seasons are preliminary. Source: National Center for Immunization and Respiratory Diseases (NCIRD)
How long is the annual flu shot effective?
The immunity from your flu shot should last for the full duration of the flu season. “Getting your flu shot each fall protects you for the current flu season, but each year, you’ll need to get your shot to stay protected,” explains Dr. Shenoy.
By getting the flu vaccines, individuals can reduce their risk of severe illness should they get the flu, and protect those around them.
Erica S. Shenoy, MD, PhD
- Chief of Infection Control, Mass General Brigham
Is the flu shot safe?
The flu shot has been extensively studied and is safe. It’s been used for over 80 years and hundreds of millions of Americans have received it.
Flu shot side effects
Like many vaccines, you can have some side effects from the flu shot. These are generally mild and go away in a few days.
Flu shot side effects may include:
- Soreness from the shot
- Headache
- Fever
- Nausea
- Muscle aches
Despite these symptoms, you can’t get the virus from the vaccine.
“The vaccines either have inactivated virus—they are no longer infectious—or particles that look like flu to your immune system. Even the nasal spray flu vaccine, which contains a live virus, cannot give you the flu since the virus has been changed to prevent infection,” says Dr. Shenoy.
Flu shot near me
There are many places to get a flu vaccine, so pick a location that’s most convenient for you. Some places may only offer the flu vaccine to patients of certain ages, or may not have the vaccines for patients 65 and older available. It’s a good idea to check in advance before you make an appointment.
Local pharmacy
Visit a local pharmacy to get your flu vaccine. Local pharmacies may not give vaccines to infants and toddlers. Please contact your child’s pediatrician’s office if you have trouble finding a pharmacy that offers flu vaccines for children.
To find a local pharmacy, visit vaccines.gov or call 1-800-232-0233.
Primary care provider’s office
Many primary care and specialty offices across Mass General Brigham offer the flu vaccine at regularly scheduled office visits. Most of our clinics do not offer vaccine-only appointments.
