IDK, I wonder that myself. I would think that employers requiring healthy people to get vaxed would be contrary to ADA and HIPAA and, certainly for going on airplanes, shipping, etc. Someones health status is nobody else's business, and yet.
As for your asthma, maybe just print out a vac card and wave it at anyone who bitches at you?
One thing that stops people that I've done is just start acting like a happy retard for real, seriously dangle drool from your lip. Tell them their shirt is so pretty. They back up and leave. Its fun.