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Influenza, otherwise known as the seasonal flu, is a virus that causes high fever, cough, sore throat, runny or stuffy nose, headache, muscle aches and fatigue. Seasonal influenza makes its way around the world causing outbreaks of disease everywhere.
In the United States, flu season is November through April, with most cases occurring December through March. The most lethal complication of influenza infection is pneumonia. Every year in the United States 5 to 20 percent of the population is infected with seasonal influenza; more than 200,000 people are hospitalized and more than 36,000 people die of seasonal influenza.
It is strongly recommended that the following individuals get the seasonal flu vaccine each year, but anyone who wants to reduce their chances of getting the flu should also get vaccinated.
Who should get the seasonal flu vaccine?
Everyone who is at least 6 months of age should get a flu vaccine. It's especially important for:
Who should not get the seasonal flu vaccine?
How do flu vaccines work?
The flu vaccine causes antibodies to develop in the body, and these antibodies provide protection against influenza virus infection.
Why should people get vaccinated against the flu?
Influenza is a serious illness, and people at any age can get it. In an average year, the flu causes 36,000 deaths — mostly among those aged 65 and older — and 114,000 hospitalizations in the U.S. The flu season in the U.S. is usually from November through April each year. During this time, flu viruses circulate throughout the population. An annual vaccine is the best way to reduce your chances of catching the flu.
When should I get a flu vaccination?
The best time to get vaccinated is from October through November. Flu activity in the U.S. generally peaks between late December and early March.
Does the flu vaccine work right away?
No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against the influenza virus. In the meantime, you are at risk for developing the flu. That’s why it’s better to get vaccinated in early fall before the flu season gets underway.
Can I get the flu even though I got a flu vaccine this year?
Yes. The effectiveness of the vaccine depends on two things:
How effective is the flu vaccine?
The flu vaccine is the most effective way to prevent the flu.
Why do I need to get vaccinated every year?
Flu viruses change from year to year, which means two things. First, you can get the flu more than once during your lifetime. The immunity that you build up from having the flu caused by one virus strain doesn’t always provide protection when a new strain is circulating. Second, a vaccine made against flu viruses circulating last year may not protect you against the newer viruses.
For More Information
To learn more about Sharp's services or to find a Sharp-affiliated physician, search for San Diego doctors or call 1-800-82-SHARP (1-800-827-4277), Monday through Friday, 8 am to 6 pm. To find general information about flu care health, visit Influenza in Adult Health or read the Infectious Diseases News archive.