Health experts advise against taking painkillers before getting a COVID-19 vaccine, but say they’re OK to use afterward if symptom relief is needed and your doctor agrees. Evidence on pain medicines and coronavirus vaccines is very limited. Some research suggests some medicines might curb the very immune system response the vaccine is trying to generate. Arm soreness, fever and aches are signs the body is mounting a defense against the virus. Check with your doctor about painkiller use after a shot. Acetaminophen, or Tylenol, might be safer than some other types of pain medicines in this situation.