https://www.theguardian.com/society/2021/jan/15/covid-vaccine-passports-what-are-they-and-do-they-pose-a-danger-to-privacy

Race to build app for people to demonstrate Covid jab or a negative test, but rights groups worry about ‘identity checks’

Vaccine passports, which would allow people with immunity to Covid to prove they were at low risk of spreading the disease, are being investigated by companies and countries around the world. But the proposals have also raised fears among critics that they could underpin an oppressive digital ID system, and put sensitive medical records in the hands of authorities and employers.