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.
Can people catch the flu from the flu shot?
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 two 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 one to two days. Because the flu shot contains inactivated, or killed, virus particles, there is no possibility of contracting the infection from the flu shot.
What are signs and symptoms of an allergic reaction to the flu shot?
Egg allergy and the flu vaccine
Formerly, those who are allergic to eggs or who have had a serious reaction to a previous flu shot were directed to discuss the situation with a doctor prior to receiving a flu shot. However, in 2017 revised guidance from the Influenza Vaccine and Egg Allergy Practice Parameter Workgroup commissioned by Joint Task Force on Practice Parameters (JTFPP) stated that the flu vaccine poses such a small risk to egg-allergic patients that even asking about egg allergy is no longer necessary. The influenza vaccine can be administered to people who are allergic to eggs without any special precautions.
Rare flu shot complications
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 who have had a previous severe reaction to the shot (Guillain-Barré syndrome) should consult a doctor before receiving the vaccine.