The Seattle chapter of BOMA has created a variety of COVID-19 related signage available for download by going to this URL: 

https://www.dropbox.com/sh/k3q7vwz7qnxcfeu/AAAh4nTY5QBgIcL-v8p04B8fa?dl=0

Hopefully you may find some signage templates you can use and prevent the re-invention of the proverbial wheel.

Doug Litwiller