An overview of seasonal influenza vaccine

The seasonal influenza vaccine is now recommended for almost everyone, every year. In 2010, the CDC's Advisory Committee on Immunization Practices recommended "universal" flu vaccination—meaning everyone 6 months and older, with rare exception, should get it—to help protect more people against influenza every year.⁶⁰

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Flu vaccine for infants and young children

Did you know that most flu epidemics are often spread by school-aged children?⁹⁴ And severe flu complications are most common among children younger than 2 years of age?⁷³ These are just a couple of reasons why it's important to not only vaccinate your own children, but to also encourage other parents to get their kids vaccinated, too.

"Many parents may not realize how serious the flu can be."⁹⁴

Flu seasons vary, but influenza continues to be a significant cause of vaccine-preventable death among children.⁹⁴ In fact, in 2009, more than 340 children died from the swine flu (H1N1). And each year an average of 20,000 children under the age of 5 are hospitalized because of flu complications.⁷³

It's recommended that kids 6 months of age and older get a flu vaccine every season. It's especially important for children under 2 years of age to get vaccinated.⁷⁴

For more detailed information about protecting your children from the flu and giving kids the flu vaccine, visit cdc.gov.

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Flu vaccine for teenagers and preteens

The flu isn't just a nasty bug that can keep your adolescent home from school, or keep you out of work caring for them. It can be serious. Each year, the flu sends, on average, more than 200,000 people people in the United States to the hospital. Adolescents with chronic medical conditions, such as asthma or diabetes, are at especially high risk for flu-related complications.⁵⁹

A flu vaccine is the best way to help protect your adolescent (and you, your family, and other children) against this preventable disease and to keep it from spreading. The CDC recommends that your adolescent get a flu vaccine as soon as it becomes available.⁵¹

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Flu vaccine for adults through age 64

While most people recover from the flu within a few days or weeks time, it can have more serious consequences than just a few missed workdays.⁵¹ The flu can lead to pneumonia, bronchitis, and serious complications including death.^51,58

Americans lose an estimated $16 billion in income due to flu-related illness and death every year.⁸³

Pregnant women and adults 50 years of age and older are at high risk for having flu complications, so the CDC says it's especially important for them to get the flu shot every year.⁷⁴

It's also important that people who live with or care for high-risk individuals get vaccinated. This includes health care workers and people in the same household as those who are at higher risk for developing flu-related complications. People who live with or care for children younger than 6 months of age should also get the flu vaccine, because these children are too young to be vaccinated themselves.⁷⁴

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Flu vaccine for seniors age 65 and older

Each year, the flu sends, on average, more than 200,000 people people in the United States to the hospital. While it can be deadly at any age, it is most deadly among adults 65 years of age and older.⁵⁹ And as seniors age, their immune system weakens, making them more susceptible to the flu. It's no surprise that 90% of flu-related deaths and more than half of flu-related hospitalizations occur in people age 65 and older.⁹⁵

All seniors should get the flu shot every year.⁹⁵

But it's especially important that seniors living in nursing homes and other long-term care facilities get their seasonal influenza vaccine.⁷⁴

There is a high-dose version of the flu shot for people 65 years of age and older. This high-dose flu shot is designed to give seniors higher antibody levels against seasonal influenza.⁹⁶ You can talk to your health care provider about which flu vaccine is better for you.

Flu vaccine side effects

What are the side effects and reactions that could occur with the flu shot? Fortunately, the risk of the flu vaccine causing any serious complications is very small.¹⁴⁸ Here's more information that may ease your concerns about influenza vaccine side effects.

You can't get the flu from a flu shot

A lot of people worry about not feeling well after the flu shot and coming down with the flu. But the truth is, the virus that is used to create the seasonal influenza vaccine isn't alive. The virus is killed, so it can't give you the flu.³⁴

The nasal spray flu vaccine contains live, but weakened flu virus, and there is a flu shot (a "recombinant" vaccine) that does not use the influenza virus in its manufacturing process.³⁴

Facts on flu vaccine reactions and side effects

Of course there's a chance of side effects like with any medical treatment. But almost everyone who gets the flu shot has no serious problems from it. Your chances of having a severe reaction to the flu shot are very low.¹⁴⁸

Here are the side effects that could occur from the flu shot:

• Fever or body aches
• Headache
• Soreness, redness, or swelling where the shot was given
• Hoarseness; sore, red or itchy eyes; cough
• Tiredness/weakness³⁴

These mild side effects usually appear shortly after getting the injection and last 1 or 2 days.

Here are the side effects that could occur from the nasal spray:

• Fever or body aches
• Headache
• Runny nose, nasal congestion or cough
• Wheezing
• Abdominal pain or occasional vomiting or diarrhea
• Sore throat
• Chills
• Tiredness/weakness³⁴

Again, serious flu vaccine side effects, like a life-threatening allergic reaction, are extremely rare. If they do happen, they usually happen between a few minutes to a few hours after receiving the vaccination.³⁴

Flu vaccine safety during pregnancy

The CDC's Advisory Committee on Immunization Practices (ACIP) recommends that pregnant women get the flu shot (but not the nasal spray vaccine) at any stage of their pregnancy. According to the CDC, the flu vaccine is a safe way for a pregnant woman to protect herself and her unborn child from the flu and any related complications. Flu shots have been given to millions of moms-to-be over many years, and they have not been shown to harm them or their babies.⁹⁷

"The flu is more likely to make pregnant women seriously ill."⁵⁷

This is because of the changes that happen to your immune system, heart, and lungs during pregnancy. Pregnant women also have a greater chance of having serious problems, including premature delivery of their babies, if they get sick.⁹⁷ If you are pregnant and have questions about getting the flu shot, speak to your health care provider.

Who may not be eligible to receive the flu vaccine?

The flu vaccine is recommended for everyone 6 months of age with rare exception. If you or your children fall into any of the following categories, speak to a health care professional before getting flu vaccine:⁷⁴

• Children younger than 6 months of age (the flu vaccine is not approved for this age group)
• People who are severely allergic to chicken eggs
• People who had a severe reaction to a flu vaccine in the past
• People who developed Guillain-Barré syndrome (GBS) within 6 weeks after getting an influenza vaccine in the past
• People who have a moderate-to-severe illness with a fever

If you wish to receive the nasal spray flu vaccine, speak to a health care professional first if you or your children fall into any of the following categories:

• Children 6 months to 23 months of age
• Adults 50 years of age and older
• Children younger than 5 years with asthma or history of wheezing
• People who have long-term health problems such as heart disease, asthma, and diabetes
• People who have a weakened immune system or live with someone with a weakened immune system
• People who are currently wheezing¹²⁶

Flu (Influenza) vaccine administration

Fortunately, there's some flexibility when it comes to when to get the flu vaccine and where you can get vaccinated.

Locations where you can get the flu vaccine

Flu shots are widely available in most United States communities. Check with your health care professional's office, within local retail pharmacies, public health clinics, supermarkets, schools, senior centers, and other places that offer the flu vaccine this season.¹⁴⁹

Here is a flu shot finder that will help you find flu vaccine locations near you.

When to get the flu vaccine

Seasonal flu vaccination usually begins as soon as the new season's vaccine is available. Because the timing of flu season can vary, vaccination should continue throughout the entire flu season.⁷⁴ Flu season usually peaks in February or later, but outbreaks can happen as early as October.⁹⁸

Finding free or low-cost flu vaccines

If you have health insurance, the cost of a flu vaccine may be covered. If not, you may be able to get free or low-cost flu vaccine at work, a local clinic, through Medicare, or your local government. Check with your employer and your state or local health department to see if they have any special flu immunization programs available.

Children may also be eligible for free vaccination under the Vaccines for Children program. Learn more at the CDC Vaccines for Children website.

Download flu vaccine immunization schedules

Infants and children under 6 years of age

Children and teens 7-18 years of age

Adults

Flu (influenza) vaccine science

Wondering what is in the flu shot or how the flu vaccine is made every year? Here you can learn about the flu vaccine inside and out.

How the seasonal influenza vaccine works

Every year, scientists from around the globe set out to determine which flu strains will be the most common in the flu season to come. Then they create the flu vaccine to protect against these strains of flu. Within 2 weeks after you get your flu vaccine, your body develops antibodies that will help protect you against infection from these strains of flu virus.⁷⁴

The difference between live weakened and inactivated flu vaccines

There are 2 kinds of influenza vaccines, there are various types of inactivated vaccines:

• The flu shot contains inactivated or killed flu virus. It is given as an injection in the arm. The flu shot is recommended for people 6 months of age and older, including healthy people and people with chronic conditions. An egg-free recombinant flu vaccine produced through genetic engineering, which does not use the influenza virus in its manufacturing process, is also available for adults 18 years of age and older.⁹⁶
• Nasal flu vaccine is made with live, but weakened, flu virus and is sprayed into the nose. This virus may be alive, but it does not cause the flu. The nasal flu vaccine is approved for healthy people 2-49 years of age who are not pregnant.⁷⁴

Is there thimerosal in the flu shot?

Multidose influenza vaccines have trace amounts of thimerosal, a mercury-containing preservative.⁷ This is because the vials contain more than 1 dose of the vaccine. The preservative is there to prevent bacterial growth in the multidose vial.⁹⁹

While many parents worry about thimerosal and the mercury that's in it, the reality is this: the small amount of mercury in the flu shot is actually much lower than the amount of mercury a breast-fed infant has every day.¹⁰⁰

But knowing some parents are still concerned, companies also offer a no-preservative version of the flu vaccine, which doesn't contain thimerosal.⁸

What is thimerosal anyway?

Thimerosal is a mercury-containing preservative. For over 50 years, it was used in multidose vaccines in small amounts to prevent them from being contaminated by bacteria. The mercury that was used (ethylmercury) is different from the environmental mercury (methylmercury) that people are exposed to when they eat some types of fish and shellfish. Unlike the kind of mercury that can make its way into the food chain, the mercury found in some vaccines is broken down and passed from the body much more quickly.⁸

The flu vaccine and autism

There has been a lot of talk about whether some vaccines cause autism, but no link has been found.⁴² In fact, thimerosal was removed from childhood vaccines 10 years ago, yet more children are being diagnosed with autism spectrum disorders (ASDs) than ever before.^8,42 This alone could be seen as evidence that thimerosal in vaccines does not cause autism.