Hundreds of academics across the world have welcomed efforts to introduce privacy-friendly contact tracing systems to help understand the spread of coronavirus.

A letter, signed by nearly 300 academics and published Monday, praised recent announcements from Apple and Google to build an opt-in and decentralized way of allowing individuals to know if they have come into contact with someone confirmed to be infected with COVID-19.

The academics said that contact tracing apps that use automated Bluetooth tracing are far more privacy preserving than apps that collect location data in a central store.

“Contact tracing is a well-understood tool to tackle epidemics, and has traditionally been done manually. In some situations, so-called ‘contact tracing apps’ on peoples’ smartphones may improve the effectiveness of the manual contact tracing technique,” the letter reads. “Though the effectiveness of contact tracing apps is controversial, we need to ensure that those implemented preserve the privacy of their users, thus safeguarding against many other issues, noting that such apps can otherwise be repurposed to enable unwarranted discrimination and surveillance.”

The academic endorsement couldn’t come at a more critical time. There are competing methods to trace individuals’ contact with coronavirus. Decentralized systems are far more privacy conscious because no single entity stores the tracing data. But the academics say that centralized stores of data can “allow reconstructing invasive information about the population should be rejected without further discussion,” and instead urged all countries to “rely on systems that are subject to public scrutiny and that are privacy preserving by design.”

“It is vital that, in coming out of the current crisis, we do not create a tool that enables large scale data collection on the population, either now or at a later time,” the letter reads.

The letter lands just days after some of the same academics pulled their support for a similar contact tracing project, known as PEPP-PT, which is said to have seven unnamed governments signed up so far. Two of those, Spain and Switzerland, have called for a decentralized contact tracing solution. But after PEPP-PT published details of its centralized proprietary protocol, several academics associated with the project disavowed the project, saying it was neither open or transparent enough, and lent their support instead to the decentralized systems, such as the privacy-friendly DP-3T protocol, or systems like Apple and Google’s cross-platform solution.

Alan Woodward, a professor at the University of Surrey who also signed onto the letter, told TechCrunch that the letter serves as what the academic community thinks is the “correct approach” to contact tracing.

“I’ve never seen anything like it in this field,” Woodward said. “It shows that it’s not just the few but many who share the concern. I really hope governments listen before they do something that will be very difficult to undo.”