As covid vaccines roll out in a handful of countries, the next question has become: How do people prove they’ve been inoculated? For months, this conversation—and the ethical questions any “vaccine passport” system would raise—has been theoretical, but over the last few weeks, efforts have become more concrete. Australian airline Qantas started running a trial in March, while New York launched the first state-level system in the US last week. And on April 5, the UK said it would conduct a pilot as part of its gradual easing of lockdown restrictions. The moves have prompted various reactions: some states in the US have endorsed the concpt; others have banned it.
