The Yellow Card, or Carte Jaune, is a medical passport issued by the World Health Organisation. It's an official record that some countries require for entrance, and it can document vaccination against diseases ranging from cholera and yellow fever to such childhood illnesses as rubella.
At the moment, there's no Yellow Card equivalent for Covid-19, and since the vaccines are so new, it would be impractical. In the United States, for example, vaccine recipients receive a small white card called a covid-19 vaccination record card that documents inoculation.
"Given this void in the market, there are a number of vaccine passport programs," says Bruce McIndoe, a senior adviser at WorldAware, a risk-management company.