On Tuesday, Germany appealed to the public to download a new smartphone app to help break the chain of coronavirus infections, one of several such apps that European governments hope will safely revive travel and tourism.

The Corona-Warn-App, which is now available for Apple and Android devices, uses short-range Bluetooth radio to measure close people-to-people contacts and issues a warning should one of them later test COVID-19 positive.

"It's not a free pass. But it's an important additional tool to contain the pandemic," Health Minister Jens Spahn said to a launch event.

Germany joins Italy, Poland, and Latvia in launching technology-based apps from Apple and Google Alphabet that safeguard privacy by securely logging Bluetooth contacts on devices.

In news coinciding with the German launch, members of the European Union agreed on technical standards for national apps to 'talk' to each other - a step towards allowing cross-border tracing of infections.

"It is important to ensure that, as we enter the travel season, Europeans can use the app from their own country anywhere they travel in the EU," Commissioner Thierry Breton said in a statement.