A yearly flu vaccine is the best way to protect yourself and your family against the flu.
But why do you need to get a flu vaccine each and every year?
Why Do You Need to Get a Flu Vaccine Each Year?
Hopefully we will one day have a universal flu vaccine that covers all flu strains and offers longer lasting protection.
Most folks know we don’t have that flu vaccine yet…
“A flu vaccine is needed every season for two reasons. First, the body’s immune response from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, the formulation of the flu vaccine is reviewed each year and updated as needed to keep up with changing flu viruses. For the best protection, everyone 6 months and older should get vaccinated annually.”
So because the protection from the flu vaccine wanes or wears off relatively quickly, even if the flu vaccine strains don’t change from one year to the next, you should get a new flu vaccine.
How long does the protection from the flu vaccine last?
“An analysis from the 2011–12 through 2013–14 seasons noted protection ranging from 54% to 67% during days 0 through 180 postvaccination.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
The flu vaccines takes about two weeks to become effective and should then last for at least six months – long enough to get you through the average flu season.
“A number of observational studies and a post hoc analysis from a randomized controlled trial have reported decreases in vaccine effectiveness (VE) within a single influenza season, with increasing time postvaccination. Waning effects have not been observed consistently across age groups, virus subtypes, and seasons; and observed declines in protection could be at least in part attributable to bias, unmeasured confounding, or the late season emergence of antigenic drift variants that are less well-matched to the vaccine strain. Some studies suggest this occurs to a greater degree with A(H3N2) viruses than with A(H1N1) or B viruses . This effect might also vary with recipient age; in some studies waning was more pronounced among older adults and younger children. Rates of decline in VE have also varied.”
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
That means it should last past the peak of the average flu season, which is typically between December and March.
And in most young, healthy people, the protection likely lasts even longer.
Still, there is some concern that the protection from the flu vaccine can wear off during a flu season, especially if you are very young, very old, or have chronic medical problems, and you get your flu vaccine early and you get exposed late – in April or May.
Of course, that’s not a good reason to delay getting a flu vaccine though, as waiting too long might leave you unprotected if flu peaks early, in October or November.
What to Know About Why You Need the Flu Vaccine Every Year
Since the flu vaccine strains can change and protection doesn’t last from season to season, get a flu vaccine each year. It’s the best way to protect yourself and your family against the flu.
More on Why You Need the Flu Vaccine Every Year
- Why do I need a flu vaccine every year?
- CDC – Key Facts About Seasonal Flu Vaccine
- MMWR – Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season
- 5 Reasons to Get Your Child the Flu Shot Now
- Flu Facts
- Study – Waning vaccine protection against influenza A (H3N2) illness in children and older adults during a single season.
- Study – Intraseason waning of influenza vaccine protection: Evidence from the US Influenza Vaccine Effectiveness Network, 2011-12 through 2014-15.
- Study – Low and decreasing vaccine effectiveness against influenza A(H3) in 2011/12 among vaccination target groups in Europe: results from the I-MOVE multicentre case-control study.
- Study – Vaccine effectiveness of 2011/12 trivalent seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: evidence of waning intra-seasonal protection.
- Study – Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015.
- Study – Influenza vaccine effectiveness: Maintained protection throughout the duration of influenza seasons 2010-2011 through 2013-2014.
- Study – Modest Waning of Influenza Vaccine Efficacy and Antibody Titers During the 2007-2008 Influenza Season.
- Study – I-MOVE multicentre case-control study 2010/11 to 2014/15: Is there within-season waning of influenza type/subtype vaccine effectiveness with increasing time since vaccination?
- 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 – Different Repeat Annual Influenza Vaccinations Improve the Antibody Response to Drifted Influenza Strains
Last Updated on April 6, 2024