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Children's Vaccines Health Center

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Seasonal Flu Shot and Nasal Spray


Why Do People Need a Flu Vaccination Every Year?

The seasonal flu vaccine is changed every year. Each year, a panel of experts from agencies such as the FDA and the CDC studies the available data and decide which three or four strains of influenza viruses will most likely be active during the next flu season. In February, they advise the manufacturers which strains of viruses to use in making the vaccine. So, each year the vaccine being used is different than the vaccine used the year before.

How Effective Is the Seasonal Flu Vaccine?

The seasonal flu vaccine is about 80% effective in preventing flu. It takes about two weeks for the body to become protected after getting the seasonal flu vaccine.

The viruses used in the vaccine may not be the only strains causing the flu; it's possible you could be infected with a virus you do not have immunity against. People who get the flu after getting a flu shot typically have a milder and shorter case of flu.

Who Should Get a Seasonal Flu Vaccine?

The seasonal flu vaccine is recommended for all children age 6 months and older and for teens.

It's also recommended for adults considered to be at higher risk of complications. That includes:

  • People with chronic diseases such as diabetes mellitus, kidney disease, heart disease, lung disease, and a weakened immune system, such as from HIV/AIDS or as a result of therapy.
  • Pregnant women
  • Residents of nursing homes and other facilities where people have chronic medical conditions
  • Health care workers
  • People planning to travel to the tropics at any time and people who were not vaccinated but are going to the Southern Hemisphere from April through September
  • People ages 50 years and older. There are now high-dose vaccines made specifically for older people and their immune systems.
  • Caregivers and household contacts of anyone in a high-risk group

The vaccine is also recommended for anyone else who wants to be protected against this year's flu.

If a child is between 6 months and 8 years and is being vaccinated against flu for the first time (or was vaccinated for the first time during the previous flu season but only got one dose) he or she should get two doses, separated by at least four weeks.

Are There Some People Who Should Not Get a Flu Vaccine?

People who should not get a flu shot include:

  • Infants under age 6 months
  • Anyone who has had a severe reaction to a past flu shot or nasal spray
  • Someone with Guillain-Barre syndrome
  • People with moderate to severe illness with a fever; they should be vaccinated after they have recovered. 

It's long been advised that people with allergies to eggs should not get the flu shot. However, the American College of Allergy, Asthma & Immunology says the vaccine contains such a low amount of egg protein that it's unlikely to cause an allergic reaction in those with an egg allergy. If you have a severe egg allergy (anaphylaxis), talk to your doctor before getting the flu vaccine. Also, flu vaccines that do not contain eggs are available.  


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