Get the facts on seasonal flu
Flu Q&A
Flu shot Q&A
It’s best to get your flu shot by the end of October, before flu season begins.
Getting it later can still help. It takes approximately 2 weeks for your body to create antibodies to the flu after getting the flu shot. The flu usually becomes widespread in winter.
Recent studies from the Centers for Disease Control and Prevention (CDC) show that the flu vaccine can reduce your risk of getting the flu by 40% to 60%.1 The effectiveness of the flu shot varies based on how well the vaccine matches the current virus, your age, and your general health.
But even if you catch the flu, getting the flu shot can make your symptoms less severe.
Yes. It’s possible to get the flu even if you got a flu shot. This may happen because:
- You caught the flu before the vaccine started to work. It takes 2 weeks for antibodies to develop and protect you from the virus.
- You got a virus that wasn’t covered by the flu vaccine. Each year the flu shot is designed to protect you from the coming season’s most common expected virus. Sometimes there’s a mismatch between the vaccine and the virus.
People ages 65 and older are now recommended by the CDC to get a high dose flu shot. High dose flu shots have been shown to be potentially more effective than standard flu shots in preventing severe illness, hospitalization, and death in older adults.2
If a high dose flu shot is not available, people in this age group should get a standard flu shot. This is better than not getting a flu shot at all.
Flu and COVID-19 Q&A
Both the flu and COVID-19 affect your respiratory system — your lungs and airways — but they’re caused by different viruses. The flu is caused by influenza virus. COVID-19 is caused by a coronavirus called SARS-CoV-2.
Some flu and COVID-19 symptoms are similar, so it can be hard to tell the difference between the two without getting a test. Visit our symptoms and treatment page to learn more about telling the difference between the common cold, flu, and COVID-19.
No. COVID-19 vaccines do not protect against the flu. However, COVID-19 vaccines do reduce your risk of hospitalization and death from COVID-19. They can also help lessen the severity of COVID-19 symptoms.
Learn more about COVID-19 vaccines and how to schedule an appointment at kp.org/covidvaccine.
Yes. It’s safe to get a COVID-19 vaccine and a flu shot at the same time.
Get the latest COVID-19 vaccine news at kp.org/covidvaccine.
Who’s at risk for flu complications?
People at higher risk for flu-related problems include:
The flu can be dangerous
Flu activity near you
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Footnotes
1“Vaccine Effectiveness: How Well Do the Flu Vaccines Work?” Centers for Disease Control and Prevention, cdc.gov/flu/vaccines-work/vaccineeffect.htm, accessed June 2, 2024.
2“Seasonal Flu Vaccines,” Centers for Disease Control and Prevention, cdc.gov/flu/prevent/flushot.htm, accessed June 2, 2024.
3“Flu Vaccines Are Important for Children,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/children.htm, accessed June 12, 2024.
4“Flu During Pregnancy,” American Pregnancy Association, americanpregnancy.org/pregnancy-complications/flu-during-pregnancy/, accessed June 2, 2024.
5“Flu & People 65 Years and Older,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/65over.htm, accessed June 2, 2024.
6“People at Higher Risk of Flu Complications,” Centers for Disease Control and Prevention, cdc.gov/flu/highrisk/index.htm, accessed June 12, 2024.