The Real Reason You Might Get Dizzy After The Flu Shot

The flu shot helps prevent the influenza virus. It changes every year depending on what scientists believe will be the most dominant influenza strain that season, according to East Meadow Medical. It's estimated that the flu shot helps prevent roughly 105,000 flu-related hospitalizations in the United States, per the U.S. Centers for Disease Control and Prevention (CDC). Despite the positive benefits, there are side effects from the flu shot that recipients should be aware of beforehand.

First, it's important to understand that flu shots are safe. Every year, tens of millions of Americans get the vaccine with little-to-no negative effects (via the CDC). However, there are mild side effects that can occur, including soreness or redness at the injection site, headache, fever, nausea, muscle aches, dizziness, and occasionally, fainting. These symptoms are completely normal, with many people feeling nothing after their flu shot, but you still should be aware of them.

However, severe reactions can occur, and it's suggested to go to the nearest hospital if you believe you are having a strong allergic reaction (via the CDC).

The flu shot works by using a deactivated version of the expected dominant influenza strain from the upcoming flu season. This teaches your body's immune system to develop antibodies that can fight against that strain, according to Cedars-Sinai. This is also why it's impossible to receive the flu from the vaccine, despite myths about the flu. Side effects differ from person to person, as each immune system will react differently to the flu shot.

For example, everyone's symptoms are different when they have the common cold. Some people develop a high fever, while others just have the sniffles, according to Prevention. The same thing is true with the flu shot, which is why you may be experiencing dizziness or fainting while someone else does not. This can be remedied by sitting for a few minutes or eating a snack before and/or after the shot, according to Healthline.

However, it's important to note that dizziness and fainting are not unique to the flu shot. The CDC has received reports of people fainting from almost every type of vaccination and is most common in teenagers. If you become dizzy after all shots, mention this beforehand to the person giving you the flu vaccine (via Healthline).