A flu shot offers protection against influenza, a virus that infects the respiratory system. Common symptoms include high fever, cough, mucus production, body aches, weakness and chills. It can last for a week or longer and is fatal in some cases. Getting a yearly flu shot greatly reduces the risk of catching the flu. This vaccine, however, can produce common flu shot reactions.
Fever
While the flu shot contains dead virus, your body may still have a febrile response to it. This means that fever---usually mild in the case of a flu shot---could result. Mayo Clinic explains that it should resolve within a couple of days. This reaction to the flu shot can be treated with acetaminophen if needed.
Aches
Some individuals complain of mild muscle aches after receiving the injection. This can also be treated with acetaminophen for a day or two.
Fatigue
A common flu shot reaction is fatigue. It can cause the individual to feel slightly ill, a condition known as malaise. This should go away within a few days but can be treated with extra rest in the meantime.
Site Tenderness
A flu shot may cause mild tenderness at the site of injection. Some people will experience reddening and minor swelling that dissipates quickly. The "2010 Lippincott's Nursing Drug Guide" explains that an induration, or a slight hardening of the skin, at the site may be present. This reaction usually requires no treatment.
Guillain-Barre Syndrome
Rarely, a person may develop Guillain-Barre syndrome after getting the flu shot. This is a condition in which the immune system attacks the peripheral nerves of the body. Symptoms include severe back pain, unsteadiness, tingling in feet or hands and difficulty speaking and breathing. In severe cases, the individual may be temporarily paralyzed or have severe difficulty breathing. Severe or rapidly worsening cases require emergency medical treatment. Most people recover from Guillain-Barre within a few weeks but it can take years. Some individuals never completely recover.
References
- U.S. Centers for Disease Control and Prevention: Key Facts About Seasonal Flu Vaccine
- Mayo Clinic: Flu Shot
- "2010 Lippincott's Nursing Drug Guide;" Amy M. Karch, R.N., M.S.; 2010
