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Why is there a new flu vaccine each year?

Dr. Lisa Fitzpatrick answers questions about the flu and the flu vaccine.

Viruses can change. What we call mutate. The flu is a virus that changes from year to year. And because of that it’s necessary to produce a new vaccine each year.

Scientists who are very informed about the flu and understand the genetics of the flu virus, they make a decision about what the most likely flu strain will be and that’s how they determine what the flu shot will be for that year.

This information is shared for educational purposes only and should not be used as a substitute for professional medical advice. The views expressed are those of the featured medical professional and reflect information available to that professional at time of filming. Always consult a health care provider for any personal health decisions. Click here for vaccine FAQs from the CDC.

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