Common Side Effects of the Flu Vaccine


The flu vaccine is the best protection against seasonal flu . That's why millions of people get the flu vaccine every year.

Although very few serious side effects have been reported, people are known to experience mild side effects after receiving the flu vaccine or nasal flu spray ( FluMist ).

This article looks at common and mild side effects and their symptoms. It also explains some of the myths about vaccines and special situations for people with a history of allergic reactions.

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Common side effects

An annual flu shot provides safe and effective protection against seasonal flu. Side effects are usually minor. They are triggered by an immune response that increases your immunity to the virus.

Common side effects of the flu vaccine and FluMist nasal spray include:

There are also side effects that are common with the flu shot or FluMist nasal spray. For example, you may have a cough after taking FluMist.

Side Effects of the Flu Vaccine

Flu vaccines are given with inactivated viruses. This means that they are dead and are not contagious. Side effects of the injection may include pain, redness, and swelling at the injection site.

FluMist side effects

FluMist Nasal Spray is a live attenuated influenza vaccine (LAIV). This means it is done with live viruses that have been weakened. They cannot cause the flu . These weakened viruses can only reproduce at lower temperatures, such as those found in the nose. They cannot survive at a normal body temperature.

Side effects of the nasal spray can include:

There is a common misconception that the flu vaccine can cause the flu . This is not true, and neither a flu shot nor a flu nasal spray will give you the flu.


The vaccines used to prevent influenza are safe and effective. Many do not contain live virus at all, and even vaccines made from a weaker form of live virus cannot cause the flu. Most people will experience little or no side effects. This is true for both commonly used flu vaccines and FluMist nasal spray.

Rare side effects

In very rare cases, people can experience severe allergic reactions after vaccination, including anaphylaxis . Signs of anaphylaxis include:

Anaphylaxis is a medical emergency. If left untreated, it can lead to loss of consciousness, shock , coma, heart or respiratory failure, and death.

This severe reaction usually occurs within 5 to 30 minutes after contact with an allergenic substance ( allergen ). In some cases, symptoms may take more than an hour to appear.

A study by the Centers for Disease Control and Prevention (CDC) found that the estimated incidence of anaphylaxis after all vaccines is 1.31 cases per million doses. The rate for a typical flu vaccine was 1.6 cases per million doses.

Anyone who has experienced a severe and life-threatening allergic reaction to the flu vaccine in the past should not receive the vaccine again in the future. It should be noted that people who have had a mild allergic reaction (such as hives the next day) can and should continue to receive the annual flu vaccine.

Egg allergy

For many years, people with egg allergies have avoided flu shots . This is because the vaccine was originally produced from chicken eggs, which represents a potential risk of reaction.

The new recombinant flu vaccines are made without eggs, making them safe for people with an egg allergy. These include Quadrivalent Flublock (for adults over 18 years of age) and Quadrivalent Fluselwax (for people 4 years and older).

You should tell your doctor if you are allergic to eggs before getting a flu shot. However, it is important to know that this should not prevent you from receiving the vaccine.

The risk of an allergic reaction to any flu vaccine is extremely low. This includes egg-based vaccines. Therefore, the CDC recommends the vaccine even for people who have a history of egg allergy or who have mild hives after vaccination.

People with a history of severe allergic reactions to eggs should get a flu shot at their doctor's office. A doctor can monitor them for signs of a reaction and treat them quickly.

Flu Vaccine and Chronic Diseases

It's true that people with chronic illnesses are at a higher risk for complications from the flu. However, they are not at increased risk of side effects from the flu vaccine. Flu vaccines have been shown to be safe for this vulnerable group of people.

On the other hand, the FluMist nasal spray vaccine is not recommended for people with certain chronic medical conditions. This is due to possible complications due to the weakened form of the live influenza virus it contains.

Vaccines and autism

For years, it has been rumored that the flu vaccine could cause autism . One claim is that preservatives like thimerosal can cause autism.

Research has shown that this is not the case. Thimerosal has a long history of safety, according to the CDC. There is no evidence of harm caused by the low doses used in vaccines.

If you are concerned about the preservatives in the flu vaccine, talk to your doctor about other options. Most single-use vials and pre-filled syringes do not contain a preservative. This is because the products are used immediately and are not transferred. The same goes for the FluMist nasal vaccine, which also does not contain preservatives.


The annual flu vaccine is safe and effective in preventing the flu. Many people report mild side effects, such as muscle pain or a mild fever, after an injection or nasal spray. These side effects are normal and do not mean that the vaccine infected you with the flu. They usually go away in a day or two.

Some people allergic to eggs, especially eggs, should be aware of the possibility of a reaction. Recombinant vaccines are an option because they are produced differently. People who have had a severe reaction to the flu vaccine should not get it again.

Get the word of drug information

If you are concerned about the safety of the flu vaccine, talk to your doctor. This is especially true if you have heard rumors that the vaccine is not safe because it can cause autism.

Frequently asked questions

  • For several days, you may have pain where you got the flu shot. If you have side effects such as a mild fever , headache , fatigue , or muscle pain , your symptoms should go away in a day or two.

  • If you receive the live attenuated vaccine in FluMist nasal spray, it is possible that you will spread the live virus within 11 days of vaccination. Isolation of this type of vaccine is more common in young children.

  • In a positive sense, yes. Research shows that a flu shot can lower your risk of having a heart attack , heart failure, and other serious heart disease during the upcoming flu season.

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