Signs & Symptoms of a Flu Shot

The flu is a respiratory virus that is common in the winter in the United States and other parts of the Northern Hemisphere. In most cases, the flu is mild. However, some people can get severely ill from the flu, and it can even be fatal. According to the U.S. Centers for Disease Control and Prevention, more than 200,000 people are hospitalized and more than 36,000 people die each year from the flu. The best way to prevent getting the flu is to get the flu vaccine. There are two types: an inactivated intramuscular vaccine and a live attenuated nasal vaccine.

Soreness

• Some people who receive the inactivated flu shot that is injected in the arm may develop redness, soreness or swelling at the injection site, according to the CDC. In most cases, the discomfort is mild and dissipates in a day or two.

Flu Symptoms

• Because the nasal flu vaccine in a live but weakened strain of the flu, it is possible to develop some mild flu symptoms within a day or two of receiving it, according to the CDC. Common symptoms include a mild fever, headaches, muscle aches, a runny or stuffy nose, and nausea or diarrhea. These symptoms are much more mild than in a full-blown case of the flu and typically subside within a day or two.

Sore Throat

• Some people who receive the flu shot may also experience a mild sore throat or hoarseness after getting the shot, according to the CDC. Itchy and watery eyes and mild fever are also sometimes reported. These symptoms typically clear up within a day or two.

Severe Reactions

• In very rare cases, people receiving the flu vaccine may have a severe or even life-threatening reaction. Signs of a severe reaction include a high fever and unusual behavior changes. Signs of an allergic reaction include hives, wheezing, coughing, weakness and dizziness. People experiencing a severe reaction should seek immediate medical attention.