Why Do You Have Arm Pain After a Flu Shot?

Side effects of the flu vaccine include pain, swelling, or redness where the shot was given. It's normal and common that getting a flu shot makes your arm sore for a day or two.

Part of the reason you experience flu shot arm pain is because of an immune system response. Read on to learn why you arm hurts after a flu shot and how to reduce soreness.

Why Does My Arm Hurt After a Flu Shot?

It's common to have arm soreness after a flu shot. The injection aggravates your muscle and makes it hurt. The flu shot is an intramuscular vaccine, which means it's injected directly into a muscle in your arm. Your deltoid muscle, which covers your shoulder joint, is the recommended site of the shot.

Your arm may also hurt as part of an immune system response. Your immune system jumps into action to react to the vaccine where it was injected: your arm. You'll experience arm soreness as a result.

An intramuscular shot like the flu, COVID-19, or tetanus shot tends to cause more arm soreness than a subcutaneous vaccine. A subcutaneous vaccine just goes under your skin, such as the measles-mumps-rubella-varicella vaccine (MMRV).

Your body's response also comes into play. Not every person who receives a flu shot will have arm soreness afterward, but many people experience it. A study published in 2019 noted that 60% to 80% of people report swelling, pain, and tenderness after a flu shot.

How To Reduce Arm Soreness

It may be possible to reduce arm soreness when you get a flu vaccine. Here are possible options before, during, and after the shot to consider for relief.

Before the Shot

There's not much you can do to prevent flu vaccine arm soreness beforehand. Avoid taking over-the-counter (OTC) medications like ibuprofen, aspirin, or acetaminophen before you get the vaccine to prevent side effects. These drugs could affect the vaccine's effectiveness.

During the Shot

You'll want to keep some things in mind when you are getting the flu vaccine. Get vaccinated in your non-dominant arm or the arm you use the least. Try to relax the arm in which you are receiving the shot.

After the Shot

You have a few options to consider after you receive a flu shot. You could do the following:

• Apply ice to the injection site
• Consider taking OTC pain relievers
• Move your arm around as comfortable, or be physically active

Doing arm movements or being physically active can reduce arm pain after the shot. The movement promotes blood flow and helps the vaccine move throughout the area where you received it. OTC medications and ice can reduce swelling or redness.

Benefits of a Flu Shot

Getting an annual flu shot is the first and most important step to protect yourself and others against the flu. Other benefits include:

• Increased protection for pregnant people, infants after birth, and children
• Reduced hospitalization risk
• Reduced illness severity
  

When To Call a Healthcare Provider

Flu vaccines have other side effects other than arm soreness. It's best to seek medical attention right away if you have:

• Difficulty breathing
• Dizziness
• Hives
• Hoarseness or wheezing
• Lip or eye swelling
• Paleness
• Rapid heart rate
• Weakness
  

A Quick Review

It's normal to feel arm pain when you get vaccinated against the flu. The pain is both a physical reaction to the shot and an immune response. Preventing or reducing arm soreness before a flu vaccine, unfortunately, may not be possible. Try relaxing your arm during the shot and taking an OTC pain reliever afterward to reduce pain.