In 2021, as COVID-19 vaccines became more publicly accessible, some governments began to authorize health
credentials either as a document or in a digital form. These "vaccine passports" are used to control public access to indoor venues (like bars, restaurants, spas, and casinos) and very large gatherings (like concerts, festivals, and sporting events) and not just to facilitate travel. Depending upon the requirements of the issuing authority, an applicant would need to provide either proof of vaccination(s), a negative COVID-19 test, proof of a recovery from the virus, or some combination of these. Their usage and implementation has been controversial and has raised various scientific, medical, ethical, legal, discrimination, privacy, civil rights, and human rights concerns. ==See also==