COVID question: "Should people avoid Tylenol after vaccination?"
Fever is an expected side effect of mRNA vaccines & the reflex is to treat it. But treating fever can, in some cases, dampen the immune response.
When a patient gets a post-vaccination fever, what should we do? 1/

For most of the #COVID19 trials, volunteers were allowed to use temperature-lowering medications (antipyretics) after vaccination. This is understandable; fever is uncomfortable and, in rare cases, can be dangerous. 2/

But most of the time it's not. Fever is an adaptive response. It helps the immune system optimize performance. B cells make some antibodies more efficiently at higher temperatures. Treating a post-vaccination fever might be a mistake. 3/ https://www.chop.edu/news/journals-fever-and-vaccines

For this reason, some doctors avoid antipyretics like Tylenol around the time of vaccination, but I'd wager that most do not. 4/

When Pfizer's vaccine data is made public tomorrow, I'll want to know if there's a difference in the immune responses of those who took Tylenol (and other antipyretics) vs. those who didn't. It could have an impact on vaccine efficacy and how I advise my patients. 5/

Addressing post-vaccination fever, a immunologist recently quipped, “The companies just have to warn people: "This is what you need to expect. Take Tylenol and suck it up for a day."
That may not be the right guidance. https://www.sciencemag.org/news/2020/11/fever-aches-pfizer-moderna-jabs-aren-t-dangerous-may-be-intense-some