They aren’t perfect, but they can help prevent you from getting sick with the flu and have other benefits.
How Long Does It Take for the Flu Vaccine to Start Working?
They don’t work immediately though.
“It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection.”
Key Facts About Seasonal Flu Vaccine
That’s why you don’t want to wait until the last minute to get your flu vaccine.
You want some time for it to start working, so that you can be sure that you are protected.
So while some folks talk about getting a flu vaccine too early, you do want to make sure that you get it in time to get protection before flu is active in your area. Still, it is never too late to get a flu vaccine. It is better to get a flu vaccine late in the flu season than to skip it all together.
What about younger kids getting their flu vaccine for the first time and who need 2 doses? When do they start getting protection?
“The first dose “primes” the immune system; the second dose provides immune protection.”
Study Looks at Flu Vaccine Dosing in Children
Although they likely have some protection after that first dose, the best protection will begin 10 to 14 days after their second dose.
More on Flu Vaccine Protection
- MMWR – Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
- CDC – Key Facts About Seasonal Flu Vaccine
- Ask the Experts about Influenza Vaccines
- When should I get the influenza vaccine?
- Ask the Experts about Flu Vaccines
- Why Some Kids Need a Second Dose Of Flu Vaccine
- Flu Facts vs. Fiction
- Immunobiology of Influenza Vaccines
- Study – Duration of Influenza Vaccine Effectiveness: A Systematic Review, Meta-analysis, and Meta-regression of Test-Negative Design Case-Control Studies.
- Study – Duration of protection provided by live attenuated influenza vaccine in children.
- Study – Detection of influenza antigen with rapid antibody-based tests after intranasal influenza vaccination (FluMist).