What is a COVID-19 vaccine passport?

A COVID-19 vaccine passport is a document that serves as proof that an individual has been fully vaccinated against COVID-19. Vaccine passports can be used to regulate international travel or to limit the access of unvaccinated people in certain spaces domestically. Some states (e.g., New York and Hawaii) have implemented vaccine passport programs that allow users to create vaccine credentials, which can be accessed and exhibited digitally through smartphones and internet browsers.