Vaccine "passports" are making headlines and eliciting emergency measures by governors in a handful of states.
So what are these credentials, exactly, and what are they used for?
What is a vaccine passport?
It's a credential that can be used to show that a person has been vaccinated. The same technology can be used to show a person's coronavirus test results. It's a way to demonstrate a person's health status, generally through a smartphone app or a QR code that has been printed.