The purpose of a flu shot is, of course, to prevent you from developing this potentially serious seasonal illness. The shot, however, might cause soreness at the injection site. If you receive your flu shot as an intramuscular injection, you have a 10 to 64 percent chance of experiencing some soreness, reports the Centers for Disease Control and Prevention. This temporary, mild arm soreness is substantially less bothersome than the whole-body achiness you’d experience if you had skipped the shot and ultimately caught the flu. While nothing can guarantee that you won’t feel some arm discomfort after a flu shot, there are some simple things you can do to reduce the likelihood and potential severity.
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Avoid Tensing Your Muscle
Tensing your arm before an injection is common. It can also be problematic, unfortunately. When you tense your arm muscle before you receive a shot, you increase the likelihood of experiencing post-injection soreness. To avoid this, give yourself time to calm down before the injection, and try taking some deep breaths. If you’re not a fan of needles, it might help to look away so you don’t tense up right before the needle punctures the skin.
Move Your Arm After the Shot
Immediately after you receive your flu shot, you might feel a little pressure and discomfort. This may lead you to hold your arm still. While this response is natural, it’s not helpful. To reduce the likelihood of achiness later, move your arm after you get your flu shot. This helps spread the injected liquid, reducing the likelihood that you'll experience muscular soreness due to a high concentration of medicine in one spot.
Don’t Skip Your Exercise
Flu shot day is not the day to skip the gym. Engaging in exercise after getting the vaccine will improve blood circulation and disperse the medication throughout your muscle tissue. As an added bonus, moderate exercise boosts your body’s immune system for several hours, report the authors of a study published in the July/August issue of the "American Journal of Lifestyle Medicine." This might improve the effectiveness of the flu vaccine.
Use a Cool Compress
If you start to notice some soreness at the injection site, acting quickly can hasten your recovery and reduce the severity of your arm discomfort. Place a cool compress on the site of your injection. This will ease your pain in two ways. First, it will numb the skin. Second, it will help reduce any inflammation you may be experiencing. Avoid putting ice in direct contact with your skin. Use a layer of towel to help disperse the coolness across the area and ensure that the cold doesn’t damage your skin.
Take a Mild Pain Reliever
If your pain continues or worsens, taking an over-the-counter pain reliever such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) could provide some relief. Although these medicines are safe for most people, check with your doctor to be sure they won’t negatively react to other medications you may be taking or aggravate any medical conditions you may have. Follow the dosing instructions on the package when taking these medications.
Warnings and Precautions
Arm soreness after a flu shot is usually mild, doesn't interfere with daily activities and goes away within a day or two. Contact your doctor if you experience severe arm pain or if your pain is not getting better within a couple of days after your flu shot.
Allergic reactions to the flu shot are very rare, but they can occur. These reactions typically occur within a few minutes to a few hours of the shot. Contact your doctor immediately if you experience body-wide itching, difficulty breathing, wheezing or hives.
- Centers for Disease Control and Prevention: Prevention and Control of Seasonal Influenza With Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2013–2014
- American Journal of Lifestyle Medicine: Moderate Exercise Improves Immunity and Decreases Illness Rates
- American Academy of Allergy, Asthma and Immunology: Treatment of Local Injection Reactions