Like other legal experts, privacy advocates and bioethicists, Shachar said using “passports” or apps that are unregulated, unreliable and rife with errors to decide who can work, travel or eat out raises troubling questions about privacy, discrimination, risk and fairness.

“There are a lot of other things to do to change the workplace” to make it safer, said Alta Charo, a bioethics expert at the University of Wisconsin Law School who has served on several national and state ethics advisory panels.

Scientists are sounding alarms, too, about both the tests, which the FDA has recently began vetting, and the gaps in knowledge.

“It is not yet clear which antibody responses, if any, are protective or sustained,” the Infectious Diseases Society of America said recently, cautioning against overreliance on these tests or any “passports” or licenses they generate until a lot more is known.