Does the Flu Shot Cause the Flu ?

October 28, 2018 | Categories: Health

(This article was published in 2014. Check out the CDC’s latest guidelines on the flu vaccine.)

You cannot get the flu from a flu shot. The risk of a flu shot causing serious harm or death is extremely small. However, a vaccine, like any medicine, may rarely cause serious problems, such as severe allergic reactions. Almost all people who get influenza vaccine have no serious problems from it.

Flu vaccines that are administered with a needle are currently made in two ways: the vaccine is made either with a) flu vaccine viruses that have been ‘inactivated’ and are therefore not infectious, or b) with no flu vaccine viruses at all (which is the case for recombinant influenza vaccine). In randomized, blinded studies, where some people got flu shots and others got saltwater shots, the only differences in symptoms was increased soreness in the arm and redness at the injection site among people who got the flu shot. There were no differences in terms of body aches, fever, cough, runny nose or sore throat.

Side Effects That Can Occur

• Soreness, redness, or swelling where the shot was given
• Fever (low grade)
• Aches

The intradermal flu shot may cause other additional mild side effects including:

• Toughness and itching where the shot was given

When To Call Your Doc

Signs of serious allergic reaction can include breathing problems, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness. If they do occur, it is within a few minutes to a few hours after the shot. These reactions are more likely to occur among persons with a severe allergy to eggs, because the viruses used in most influenza vaccines are grown in hens’ eggs. While severe reactions are uncommon, you should let your doctor, nurse, clinic, or pharmacist know if you have a history of allergy or severe reaction to flu vaccine or any part of flu vaccine, including eggs.

The seasonal flu vaccine protects against the three or four influenza viruses that research indicates will be most common during the upcoming season.

Who Should Get the Flu Shot

Everyone who is at least 6 months of age should get a flu vaccine this season. This recommendation has been in place since February 24, 2010 when CDC’s Advisory Committee on Immunization Practices (ACIP) voted for “universal” flu vaccination in the United States to expand protection against the flu to more people.

People who are at high risk of developing serious complications (like pneumonia) if they get sick with the flu.

• People who have certain medical conditions including asthma, diabetes, and chronic lung disease.
• Pregnant women.
• People younger than 5 years (and especially those younger than 2), and people 65 years and older.
• Can the nasal spray flu vaccine give you the flu?
• The nasal spray vaccine cannot give you the flu. The viruses contained in the nasal spray flu vaccine are attenuated (i.e., weakened), which means they cannot cause flu illness. These weakened viruses are also cold-adapted, meaning they are designed to only cause mild infection at the cooler temperatures found within the nose. These viruses cannot infect the lungs or other areas of the body where warmer temperatures exist. The nasal spray is well tolerated and the most commonly reported side effects are mild and include runny nose, nasal congestion and
• Why do some people not feel well after getting the seasonal flu vaccine?
• Some people report having mild reactions to flu vaccination. Common reactions to the flu shot and the nasal spray flu vaccine are described below.
• Reactions to the flu shot:
  The most common reaction to the flu shot in adults has been soreness, redness or swelling at the spot where the shot was given. This usually lasts less than two days. This initial soreness is most likely the result of the body’s early immune response reacting to a foreign substance entering the body. Other reactions following the flu shot are usually mild and can include a low grade fever and aches. If these reactions occur, they usually begin soon after the shot and last 1-2 days. The most common reactions people have to flu vaccine are considerably less severe than the symptoms caused by actual flu illness.
• Reactions to nasal spray flu vaccine:
  People also may have mild reactions to the nasal spray vaccine. Some children and young adults 2-17 years of age have reported experiencing mild reactions after receiving nasal spray flu vaccine, including runny nose, nasal congestion or cough, chills, tiredness/weakness, sore throat and headache. Some adults 18-49 years of age have reported runny nose or nasal congestion, cough, chills, tiredness/weakness, sore throat and headache. These side effects are mild and short-lasting, especially when compared to symptoms of seasonal flu infection.

This article was originally written for HealthAdvisor.com.

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