Originally Posted by Mojo31

For the doctors in the house. Pfizer now says its vaccine is good for 6 months. Is that because (a) that's all the data they have, or (b) because it loses effectiveness?

Pfizer, BioNTech Say Covid-19 Vaccine Protects for Six Months (msn.com)

I wish these articles would explain the reasoning behind the conclusion. The way it's written suggests that you might have to redo every six months.