Jan 18, 2018, 11:29:26 AM CST Jun 23, 2022, 12:22:54 PM CDT

How the flu shot works and why kids need one

Should kids get the flu shot? Getting the flu shot every year is essential to keeping your family healthy. Learn why.

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The best offense during a tough flu season is a good defense. You can protect your family from the flu by ensuring everyone in your household gets a flu shot every year.

But why do you have to get a flu shot every year? And how effective is the flu shot this year? Preeti Sharma, M.D., pulmonologist at Children's Health℠ and Associate Professor at UT Southwestern answers seven common flu shot questions.

Who should get a flu shot?

The flu shot is recommended for every person 6 months of age and older. The flu shot for kids is the same as the flu shot for adults. However, children who are 6 months to 8 years old will need two doses of the flu vaccine if they are getting vaccinated for the first time. Your family may especially need a flu shot if someone in your household is at high risk for life-threatening flu complications due to a chronic health condition. Your family member may be at high risk if they are under the age of 5 or over the age 65, or if they have:

Physicians also recommend the flu shot if you or someone in your household is pregnant.

When should you get a flu shot?

Typically, it's best to get the flu shot in early fall. It can take up to two weeks for the antibodies to develop after the vaccine is administered, so it's most effective to get the flu shot before flu season hits. For the 2021-2022 flu season, the Centers for Disease Control and Prevention (CDC) recommends getting the flu shot before the end of October, if possible.

If you miss the early window for getting the flu vaccine, Dr. Sharma advises it's better late than never. Some flu seasons stretch out for months. Getting the flu vaccine at any time will help reduce your family's risk of getting sick and reduce the chance of flu-related complications.

How often should you get the flu shot?

It's important to get the flu shot every year. The antibodies that fight influenza stay at high levels for several months after you receive the vaccine. However, over the course of several months, the body's immune response from the vaccination begins to decline. As the flu shot effectiveness wears off so does a person's protection from the flu.

Because flu viruses are constantly changing, the type of flu you may get can change every year, too. Dozens of viruses cause the flu. Each year, the flu shot contains three or four different types of inactivated flu viruses that may not have been in the flu shot the year before.

Worried you could still get the flu even if you get the flu shot? A 2021 study found that the vaccine reduces illness for people who still catch the flu. People who got the flu vaccine and then contracted the flu are at a 26% lower risk of intensive care unit (ICU) admission and a 31% lower risk of dying from the flu, compared to people who did not get the flu vaccine.

Can you get the flu vaccine at the same time as the COVID‑19 vaccine?

Flu vaccines and COVID‑19 vaccines can be given at the same time per CDC guidelines. The COVID‑19 vaccine is currently authorized for anyone 6 months and older.

How does the flu shot work?

The flu vaccine is designed to stimulate your immune system to make special proteins called antibodies. The standard flu vaccine uses inactivated, "killed" virus particles to cause your body to make antibodies to the flu virus.

After two weeks of receiving the flu vaccination, your body has enhanced immunity to the flu. If live flu viruses enter your body, the antibodies your body made after getting the vaccine will help destroy them before they can make you sick. This prevents you from getting the flu or can make a case of the flu less severe.

Does that mean that getting the flu shot can give you the flu? No, says Dr. Sharma. Because the vaccine is made with inactivated flu viruses, you cannot get the flu from the flu shot. The viruses are dead and cannot spread or multiply.

Is the flu shot effective?

Each year, companies make a new type of flu vaccine to try to be as effective as possible at preventing the flu. Recommendations from the World Health Organization (WHO) drive the development of the most effective yearly vaccination.

Because dozens of viruses can cause the flu, the WHO looks at what types of flu affected the community the year before. They also look at what strains (types) of flu were most common in Australia and New Zealand. By looking at those factors, researchers can help predict and target what strains of the flu to include in the vaccine.

Every year, the CDC evaluates how effective the current flu shot is. The effectiveness can vary, depending on what strains of the flu circulate in the community.

Even if the vaccine is less effective at preventing one strain of the flu, it may help protect you against another strain of the flu and decrease the severity of your symptoms. That's why you should get a flu shot even if the vaccine is less effective than normal.

Is it safe to get the flu shot?

The flu shot is very safe for the general population. Because of the way the vaccine is made, it contains some egg products. However, new research shows that the flu shot is safe for people with egg allergies. If you have had a reaction to the flu shot before, you should speak to your doctor.

As with any medical treatment, the flu shot may cause some side effects. Most are mild and will only last a few days.

What are other ways I can prevent the flu?

To avoid contracting the flu, it's best to avoid crowds of people and people who are sick if possible. If you are sick with the flu, it is recommended that you stay home from work, school and other public places, especially if you have a fever.

Frequent and proper hand washing is also an important flu prevention strategy. Wash your hands with soap and warm water for 20 seconds, especially before eating or touching your face. Cover up sneezes and coughs with tissues or by putting your face in the crook of your arm. See more tips for helping your family stay flu free.

See more information about the flu nasal spray vs. flu shot vaccine options.

Getting a flu shot is the best way to protect your family this flu season. Learn about recommended ages, how the shot works and when to immunize.

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