What are the side effects of the flu shot?
Medically reviewed by Drugs.com. Last updated on Aug 28, 2024.
The most common side effects of the influenza (flu) vaccine include soreness, redness, and a slight swelling around the injection site AND mild flu-like symptoms such as a headache, a slight fever, muscle aches, and nausea. Most people experience few, if any, side effects.
Injection site reactions:
Because most flu vaccines are given as an injection into a muscle, the most commonly reported side effects involve those associated with a needle piercing the skin, such as soreness, redness, and a slight swelling around the injection site. A slight, sharp pain may be experienced as the shot is delivered; however, this is usually short lasting. FluMist is a flu vaccine that is given as a nasal spray, but it isn’t for everybody. Side effects associated with FluMist include a runny nose, headache, sore throat, and cough.
Other common side effects:
The influenza vaccine contains proteins that stimulate your immune system to make antibodies against the influenza virus. The flu vaccine will not give you the flu but may cause mild flu-like symptoms, such as a headache, a slight fever, muscle aches, and nausea. These usually go away within a few days. People who are prone to fainting may faint when they are administered the flu shot, just like they would with any other vaccine.
Allergic reactions:
Very severe or life-threatening allergic reactions to the flu vaccine are rare. Symptoms usually come on within a few minutes of having the vaccine and include difficulty breathing or wheezing, dizziness, facial or throat swelling, hives or an extensive rash, a fast heartbeat or chest pain, and sometimes collapse. If you or someone you know is having a severe allergic reaction to the flu vaccine call 911.
The best way to reduce your chances of catching the flu every year is to get a flu shot. In fact, the CDC (Centers for Disease Control and Prevention) recommends everybody over the age of six months receive the flu vaccine every year, with a few exceptions.
For more information see Influenza Vaccine
Related questions
Read next
COVID-19 vaccines and variants: What you should know
The top 3 SARS-CoV-2 variants in the U.S. in early December 2024 are all of Omicron lineage and include:
- XEC (44%)
- KP.3.1.1 (39%)
- MC.1 (6%)
The original Omicron variant, first identified in Botswana and South Africa in late November 2021, is no longer circulating. Other variants may spread worldwide, and new variants may occur over time. Continue reading
Why does my child have leg pain or trouble walking after a fever?
Leg pain or difficulty walking in children after a fever can sometimes be caused by a condition called benign acute myositis. This condition occurs when muscle inflammation, usually in the calves, develops after a viral infection such as the flu or a respiratory illness. Continue reading
Can you overdose on Nyquil?
Yes, you can overdose on Nyquil if you take more than recommended, give a child more than is recommended, or you give Nyquil to a child who is under the age of 6 years. Continue reading
Related medical questions
- How long is the flu contagious for?
- Should I wear a face mask to protect myself from COVID-19?
- How long does the flu last for?
- Can Ivermectin be used to treat COVID-19?
- Can you take Ibuprofen if you have COVID-19 (coronavirus)?
- What antibiotics kill Covid-19 (coronavirus)?
- What's the difference between Bacteria and Viruses?
- How do I Treat Nasal Congestion with COVID-19?
- Phenylephrine vs Pseudoephedrine - How do they compare?
- Can vitamin C prevent or treat COVID-19 (coronavirus)?
- How long does it take for Tamiflu to work?
- Can you take expired NyQuil?
- Does NyQuil have alcohol in it?
- How long does the cold/flu virus live on surfaces?
- Does NyQuil put you to sleep?
- How long does it take for NyQuil to kick in?
- Does Mucinex help with a sore throat?
- Is Nyquil safe to take while breastfeeding?
- Can Colchicine be used to treat COVID-19 (coronavirus)?
- How and where is a flu shot injection given?
- Does the BCG vaccine for TB help with COVID-19 (coronavirus)?
- What flu vaccine can I use with an egg allergy?
- FluMist or Flu Shot: Which is more effective?
- How long can the Coronavirus survive on surfaces?
Related support groups
- Influenza (116 questions, 98 members)
- Influenza Prophylaxis (12 questions, 4 members)