Immunity passports to travel during the COVID-19 pandemic: controversies and public health risks.

As countries emerge from pandemic lockdown, many countries are relaxing international travel restrictions. Commercially available serologic tests for anti-SARS-CoV-2 antibodies are being performed. The concept of an 'immunity passport' has gained popularity, whereby evidence of SARS-CoV-2 antibody production would signal immunity to reinfection. For an immunity certificate to be validated for travel purposes, it should meet certain criteria. The introduction of such certificates faces multiple challenges. While there may be a future role for immunity passports in limited circumstances in the event that a protective vaccine becomes freely available, for now at least the risks of such an approach outweigh the perceived benefits.