allergic reaction to the vaccine or its ingredients. adults with weakened immune systems may have a lower response to the vaccine. the most common side effects were pain and swelling at the injection site, muscle pain, fatigue, headache, and joint pain. i want to be able to keep my plans. that's why i chose to get vaccinated with prevnar 20. because just one dose can help protect me from pneumococcal pneumonia. ask your doctor or pharmacist about getting vaccinated with prevnar 20 today. ♪♪