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COVID Arm: What To Know

Written by Ada’s Medical Knowledge Team

Updated on


  • COVID arm is a rare side effect of the COVID-19 vaccine that produces redness, soreness and/or itchiness near the injection point
  • The onset of symptoms is unique in COVID arm, appearing 5-9 days after the injection
  • COVID arm is harmless, and most cases resolve themselves in less than a week
  • Pain medications, antihistamines, and cool compresses can provide relief for COVID arm symptoms

Over 13 billion doses of the COVID-19 vaccine have been administered worldwide as of May 2023. Shortly after receiving the vaccine, it’s common to experience some mild side effects. One of the talked about effects is what has been called “COVID arm.” This is a delayed but harmless reaction that occurs near the injection point. It’s characterized by a rash or soreness that appears 5-9 days after the injection.

What is COVID arm?

“COVID arm" is a term used to refer to soreness, redness, and itchiness that appears around the injection site of a COVID-19 vaccine. Unlike other vaccine reactions that appear a day or 2 after the vaccine is administered, COVID arm typically appears 5-9 days after the first shot. Studies have found that these reactions may occur sooner after the second dose. 1 They’re also less likely to occur with a second dose in a person who didn’t have a reaction to the first dose of the vaccine.

Health researchers believe that COVID arm is part of the body’s natural response to the vaccine. When a vaccine is injected into a muscle, your body responds by producing antibodies and fighter cells to fend it off. However, in some individuals, this reaction can become hyperactive and cause the muscle cells to act as if they’re fighting an actual infection. 

This overreaction can result in the following symptoms at the point of injection:

  • Redness
  • Swelling
  • Warmth
  • Hardness
  • Itchiness
  • Discomfort
  • Welt
  • Rash

It’s important to note that "COVID arm" is different from a rapid onset allergic reaction to a vaccine that occurs mere hours after a vaccine is received and can be life-threatening, affecting breathing and heart rate. Individuals with severe allergic reactions must seek immediate medical attention and be treated with epinephrine, as per the CDC's guidelines and should not receive the same type of vaccine in the future.

What else can cause arm redness or soreness?

In some cases, COVID arm has been confused with other skin conditions, such as cellulitis. Cellulitis is a bacterial skin infection that presents as inflammation that can expand quickly if untreated. Contamination of the vaccine vial or unsanitary injection conditions could cause cellulitis after vaccinations. 2

Other causes of arm redness or soreness include: 3

  • Abscesses
  • Insect bites
  • Drug reactions
  • Hives
  • Sweet syndrome 

How long does COVID arm last?

The duration of COVID arm that arises from the COVID vaccine varies from person to person. Most symptoms associated with COVID arm clear within 24 hours to a week – with 3 to 4 days being the most common time it takes to subside. In some cases, COVID arm has persisted up to 21 days. 4

How do you treat COVID arm?

There are several ways to treat the discomfort associated with COVID arm. These include: 5

  • Over-the-counter pain medications: Pain relievers, such as ibuprofen or acetaminophen, can be effective in reducing arm soreness after a vaccine shot.
  • Antihistamines: Medications like Benadryl can help relieve any itchiness at the injection point.
  • Cold compresses: Applying a cold compress or ice pack to the area can help reduce swelling and discomfort.
  • Gentle arm movements: Moving the arm gently and regularly can help to reduce stiffness and soreness.
  • Rest: Taking a break and resting the arm can also help to reduce discomfort.
  • Heat therapy: Using a warm compress, such as a heating pad, can also help to relieve arm soreness after a vaccine shot.

If you experience COVID arm after your shot, tell your vaccination provider. Your vaccination provider may recommend that you receive your next COVID-19 vaccine in the opposite arm if possible.

Wrapping it up

COVID arm is a common side-effect after a COVID-19 vaccine caused by your body's immune response to the shot. The onset of the symptoms is typically 5-7 days after the shot was administered, and symptoms typically clear in less than a week on their own. 

Although these delayed injection site reactions may be a nuisance, they’re harmless. However, if the soreness persists or becomes severe, seek medical advice.


Q: Why is my arm sore after the COVID vaccine?
A: Arm soreness is a typical response to a vaccine. It can occur due to damage to the muscle from the needle and because of the body’s natural response to the vaccine. 

Q: How long does COVID arm last?
A: The symptoms of COVID arm typically resolve within a week or 2 after symptoms appear. In rare cases, symptoms can persist up to 21 days.

Q: Will COVID arm go away by itself?
A: Yes. COVID arm usually resolves itself.

Q: Should you move your arm after COVID vaccine?
A: Moving the arm gently and regularly can help to reduce stiffness and soreness.

Q: Is COVID arm contagious?
A: No. COVID arm is not contagious. It’s caused by a reaction to the vaccine.

Q: Is COVID arm an allergic reaction?
A: COVID arm is a delayed allergic reaction to the COVID vaccine that will clear itself after a week or 2.