Researchers at Boston University and MIT are collaborating on a smartphone app that will alert people if they’ve been near someone who has tested positive for the coronavirus or come down with the disease, while protecting the privacy of everyone involved.

The Baker administration has launched a more traditional approach to what's known as contact tracing with its COVID-19 Community Tracing Collaborative. But a manual survey — asking an infected person who they have been in contact with and trying to track those people down — has its limitations. That person may not remember or even know everyone they've been in contact with.

The BU and MIT researchers and other organizations have formed a group called PACT, or Private Automatic Contact Tracing, to use technology to get around those limitations. Their cellphone-based method also has its own limits, though.

Ran Canetti, a professor of computer science at Boston University and a researcher involved in the project, said the app relies on short-range Bluetooth signaling that sends out a random string of numbers called “chirps.” Smartphones that are close by pick up and store them. The app also tracks the distance and length of time spent in close contact.

“So our method of telling whether two people or two phones were near each other is not via location. It’s via phone-to-phone contact,” Canetti said.

Other countries like China, South Korea and Israel have turned to other coronavirus tracking apps. That approach allows them contain infections by imposing targeted quarantines. It has helped curb the spreadin those countries, but because they’re using GPS technology, it comes at the risk of violating people's privacy.

“Now there is a central database that only the government knows, that knows where everybody is at any point in time,” Canetti said.

Canetti said the app he and his colleagues are creating makes privacy a priority. Their app depends on voluntary participation and carrying a smartphone when the contact occurs. If a person tests positive or has been diagnosed with COVID-19, a health care professional would enable them to voluntarily upload their phone's chirps into the app’s database. Anyone else who has the app — say, a supermarket employee who's in contact with people all day, or another shopper — would then be notified that they had been in close proximity to someone who has been infected.

The system will allow users to further sign into the system, he said, provide their identities and their locations to the health authorities so they can follow up.

When the researchers reached out to Louise Ivers, the executive director of the Massachusetts General Hospital Center for Global Health, for help, she said she saw this initiative as one part of a comprehensive system, one that would work in tandem with manual tracking. But isn’t knowing a location critical to understanding where a disease is spreading?

“In order for us to control this epidemic, like every epidemic, we do have to be able to detect the cases, trace the contacts and the exposed people and isolate them. It's also important to be able to identify where there are large numbers of people in clusters," Ivers said. "So location is one important part of the overall architecture of trying to control an outbreak. But it doesn't preclude the fact that manually tracing everyone's contacts, who they've been close to, whether location is a factor or not, is still very hard to do.”

PACT is working with both Google and Apple so the app will be available for iPhones and Android phones. Canetti of BU said they're aiming to have it done within the next couple weeks.

Ivers is hopeful that once the number of COVID-19 cases start to dwindle, this app can be a good resource when the country starts to return to some semblance of normalcy outside the home.

“I can envision a not too distant future when we do start going back about our business, but the virus hasn't completely gone away yet. It may even be more manageable to think that you can move around, but now you have the possibility of being alerted if, in fact, you did get in contact with somebody,” Ivers said.