In the absence of government guidelines, businesses decimated by the pandemic are exploring how to use vaccines and testing to restore consumer confidence. The global airline industry, facing $157 billion in losses through next year, is leading the way with trials of competing digital apps that display test results and, soon, vaccination records.

Most work the same way: A certified medical clinic or laboratory uploads test results or inoculation records to an app that generates a QR code to present at check-in or immigration without revealing private information. Some of the apps employ blockchain technology to enable users to maintain privacy while sharing data, while in others the data may be stored in a central repository or on people’s phones.

The International Air Transport Association (IATA), the global airline lobby, is working on its own mobile app called Travel Pass, which it’s trialing with British Airways parent IAG SA this year before it arrives on Apple Inc. and Android devices in the first quarter of 2021, says Nick Careen, the organization’s senior vice president of airport passenger cargo and security. It’s based on the existing IATA Timatic system used by airlines and airports, including Heathrow, to verify documents such as passports, which may give it an edge over competitors.