1) The first reason is that because flu viruses are constantly changing, flu vaccines may be updated from one season to the next to protect against the most recent and most commonly circulating viruses.
2) The second reason that annual vaccination is recommended is that a person’s immune protection from vaccination declines over time and annual vaccination is needed for optimal protection.
Everyone is at risk for seasonal influenza.
Health experts now recommend that everyone 6 months of age and older get vaccinated against influenza. While everyone should get a flu vaccine each flu season, it’s especially important that the following groups get vaccinated either because they are at high risk of having serious flu-related complications or because they live with or care for people at high risk for developing flu-related complications:
• Pregnant women• Children younger than 5, but especially children younger than 2 years old • People 50 years of age and older • People of any age with certain chronic medical conditions • People who live in nursing homes and other long–term care facilities • People who live with or care for those at high risk for complications from flu, including: o Health care workers o Household contacts of persons at high risk for complications from the flu o Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated). (Some children 6 months to 8 years of age may need 2 doses of the vaccine to be fully protected. Ask your doctor.)
After vaccination, your immune system produces antibodies that will protect you from the vaccine viruses. In general, though, antibody levels start to decline over time — another reason to get a flu shot every year.
What kinds of flu vaccines are available?
There are two types of flu vaccine available:
• The "flu shot" — an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions.
There are three different flu shots available:
- a regular flu shot approved for people ages 6 months and older
- a high-dose flu shot approved for people 65 and older, and
- an intradermal flu shot approved for people 18 to 64 years of age.
• The nasal-spray flu vaccine — a vaccine made with live, weakened flu viruses that is given as a nasal spray (sometimes called LAIV for "Live Attenuated Influenza Vaccine"). The viruses in the nasal spray vaccine do not cause the flu. LAIV is approved for use in healthy* people 2 through 49 years of age who are not pregnant.
Can the vaccine give me the flu?
No. The flu vaccine can't give you the flu. But you might develop flu-like symptoms — despite getting a flu shot — for a variety of reasons, including:
- Reaction to the vaccine. Some people experience muscle aches and fever for a day or two after receiving a flu shot. This may be a side effect of your body's production of protective antibodies. The nasal vaccine can cause runny nose, headache and sore throat.
- The two-week window. It takes about two weeks for the flu shot to take full effect. If you're exposed to the influenza virus shortly before or during that time period, you might catch the flu.
- Mismatched flu viruses. In some years, the influenza viruses used for the vaccine don't match the viruses circulating during the flu season. If this occurs, your flu shot won't protect you.
- Other illnesses. Many other diseases, such as the common cold, also produce flu-like symptoms. So you may think you have the flu when you actually don't.
What are the benefits of getting the flu vaccine?
- Protection for yourself.
- Protection for newborns and infants who are too young to get vaccinated.
- Protection for people at high risk for complications from flu.
Even though the Influenza Vaccine is not approved for use in children younger than 6 months so they should not be vaccinated, but their caregivers should be vaccinated instead. And people who are sick with fever should wait until their symptoms pass to get vaccinated. Some people should not be vaccinated before talking to their doctor. This includes:
• People who have a severe allergy to chicken eggs.
• People who have had a severe reaction to an influenza vaccination in the past.
• People who developed Guillian-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine previously.
(If you have questions about whether you should get a flu vaccine, consult your doctor.)
visit www.cdc.gov, or call CDC at 1-800-CDC-INFO