BERLIN, April 22 (Reuters) - A design for smartphone technology to trace coronavirus infections, that is in line with the approach taken by Apple and Google, is gaining momentum in Europe after winning support from Switzerland and Austria over an alternative German-led approach.

Governments, having slowed the pandemic with economically disruptive lockdowns, see contact tracing apps as a tool for responding quickly to any fresh outbreaks of COVID-19.

Switzerland said it would launch an app on May 11 based on a standard, developed by researchers in Zurich and Lausanne, that uses Bluetooth communication between devices to assess the risk of catching COVID-19.

Both Switzerland and Austria favour the design, called Decentralised Privacy-Preserving Proximity Tracing (DP-3T here), saying it offers the best privacy protection because sensitive personal data is kept on devices and not on a central server.

The German-led effort, Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT), faced criticism in an open letter signed by 300 scientists that its approach “would allow unprecedented surveillance of society at large”.

In Austria, where more than 400,000 people have already downloaded the Red Cross’s Stopp Corona app, developers are upgrading its design and architecture after a review by privacy experts.

“Once the Austrian Red Cross quickly changes to a standard like DP-3T, this app could also be used quickly in other countries,” said privacy campaigner Max Schrems, who provided feedback for the Stopp Corona app.

National apps need to be able to ‘talk’ to each other across borders, to reduce contagion risks that would arise as international travel restrictions are lifted.

They would also need to be adopted by 60% of the population to achieve so-called ‘digital herd immunity’ against COVID-19, say researchers at Oxford University’s Big Data Institute.

Yet some apps are being rushed out before common standards are agreed. It’s also not clear that digital contact tracing is effective - early adopters including Singapore have had teething troubles.

WHERE’S BIG BROTHER?

Technologists agree that Bluetooth can be a powerful way to measure the proximity of contacts between individuals, while being less invasive than the location tracking used in countries like China or South Korea.

Where they disagree is on where Bluetooth contacts should be logged - on devices or on a central server. Apple and Alphabet’s Google back a decentralized approach that would only route information through a server if a notification is issued.

They have pledged to provide new application interfaces in May to support decentralized apps, and later incorporate contact tracing into their iOS and Android operating systems, which run 99% of smartphones.

Importantly, Apple has resisted calls from Germany and France to allow the Bluetooth monitoring needed to support centralized apps to run on its iPhones in the background. This means that phones must be unlocked for the app to work - a drain on the battery and an inconvenience for the user.

Kenny Paterson, a professor at the Institute of Information Security in Zurich who is involved in DP-3T, dismissed suggestions that Apple and Google were imposing unreasonable conditions for contact tracing apps.

“We have been talking to Apple and Google for weeks and we were delighted with the approach they proposed,” Paterson told Reuters, adding that it was “entirely compatible” with DP-3T. (Reporting by Douglas Busvine; Editing by Elaine Hardcastle)