This analysis by leading health law and bioethics scholar Hank Greeley examines challenges with using “immunity cards,”
“immunity certificates,” “Covid passports” or other such devices as part of the process of “reopening” society before robust treatments and/or effective vaccines become widely available.

First, it is unknown whether reinfection immunity arises following SARS-CoV-2 infection, or if so, for how long, as the length of immunity conferred will only be known as more time passes. The presence of antibodies is no guarantee that reinfection will be prevented. Immunity to other Coronavirus-caused illness, such as those causing the common cold, only lasts for a few months.

Second, while antibody tests are being developed, they likely will (a) be pushed into use before their accuracy has been optimized, and (b) as a result, deliver a not insignificant number of false positive results. This would result in people who believe they are immune reentering and engaging in the community, potentially contracting the disease, and passing it on to others.

Third, questions arise as to what should be used as “proof” to garner such certificates, and how to appropriately verify applicant claims and identities. Positive tests? Many have been unable to get such tests and/or have been told not to try. Furthermore, if the stakes are high enough, there certainly will be illicit markets developed to offer the requisite proof or versions of the cards.

And then there are the harder issues: even if we can create a reliable immunity certification process, who would run it, and under what circumstances could it be used? Will only those with certificates be permitted to work in certain positions? Or to travel? Or attend classes in person? Should that be the case? How will federal or state anti-discrimination laws, such as Equal Employment or the Americans with Disabilities Act, be triggered under such circumstances?