The EU Commission plans to award a contract this month for a central system for verifying the digital passes, which will use QR codes that can be scanned into a smartphone app. It will also provide a template to help member countries develop their own apps – though some have already readied their own versions.

There is still no consensus on whether antibody tests provide sufficient proof that a person who has recovered from COVID-19 is immune, sources involved in the efforts say.
Member states also worry about the security of personal information, though the Commission has promised the online certificates will contain minimal data: name, date of birth, the specific health information, its date of issue and a unique identifier code.