Flu Shot Side Effects

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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Many people worry about side effects from the flu shot, but serious complications are rare. Some people believe that they can actually get the flu from receiving the shot, but this is not the case. For the majority of people, the risks of developing the flu are far greater than any risks associated with the vaccine.

Most side effects and reactions to the flu shot are mild. Most commonly, people experience a soreness, redness, or mild swelling at the site where the shot was given. These effects generally do not last for more than 2 days. In rare cases, people may develop other mild reactions to the flu vaccine like fever and aches, which may mistakenly lead them to believe that they developed the flu as a result of the vaccine. These symptoms also go away after about 1 to 2 days. Because the flu shot contains inactivated, or killed, virus particles, there is no possibility of contracting the infection from the flu shot.

Allergic reactions to the flu shot are very rare. Symptoms of an allergic reaction can include problems with breathing, hives, wheezing, pale skin, a rapid heart rate, and dizziness. People who are allergic to eggs are more likely to have an allergic reaction to the flu shot because the viruses used to make the vaccines are grown in chicken eggs. Those who are allergic to eggs or who have had a serious reaction to a previous flu shot should always discuss the situation with a doctor prior to receiving a flu shot.

Another extremely rare potential complication of a flu shot is Guillain-Barré syndrome. This is a disease characterized by nerve damage, weakness, and fever that developed in some cases in association with the swine flu vaccine in 1976. Only one research study has shown any association of Guillain-Barré syndrome with subsequent flu shots developed since 1976. That study showed that only one person out of 1 million vaccinated persons may be at risk of Guillain-Barré syndrome associated with the vaccine.

It's recommended that everyone over 6 months of age receive the flu vaccine. The risks of complications from the flu are more serious than any potential risks of the flu shot. Only those people allergic to eggs and those who have had a previous severe reaction to the shot (an allergic reaction or Guillain-Barré syndrome) should consult a doctor before receiving the vaccine.

REFERENCE: FLU.gov.