TYLENOL’S FINE, BUT NSAIDS ARE NOT: Avoid preventive pain relievers before getting a COVID vaccine. “The side effects from the vaccines are caused by activation of the immune system, meaning that the immune system is working and starting to build immunity to COVID-19 — this is what we want. These pain relievers are anti-inflammatory medications. They prevent parts of the immune system from working and slow down the immune response.”
This may — it’s speculation, not research at this point — reduce the effectiveness of the vaccine by blunting the immune response.