Why do I need a new flu shot every year?

A flu vaccine is needed every season for two reasons: 

  1. The body’s immune response from vaccination declines over time, so an annual vaccine is needed for optimal protection. 
  2. 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.

Show All Answers

1. What types of flu vaccine are available?
2. When does the flu season start? When does it end?
3. Can a flu shot give me the flu?
4. Is this year's vaccine a good match?
5. Why do we count pediatric flu deaths and not adult flu deaths?
6. What is the difference between a pandemic and a normal flu season?
7. When should I get vaccinated?
8. Does the flu vaccine work right away?
9. Does the flu shot wear off if I get it too early?
10. What protection does the flu vaccine provide if I do get sick with flu?
11. Why do I need a new flu shot every year?
12. Where can I get a flu vaccine?