You might know Bluetooth best for helping you pair your headphones and smartphone, but the 21-year-old wireless technology is getting a new wave of attention now that it’s at the heart of contact-tracing apps designed to show whether you might have been exposed to the novel coronavirus. 

Google and Apple, for example, are building a system to track contact between people who might spread the disease. The idea is simple: since Bluetooth is constantly scanning for other devices, your phone can use wireless signals to see who you’ve been near. Somebody who gets a positive diagnosis can tell the app, which will inform everyone else who has been in proximity to alert them about risks of possible transmission.

Some limitations have to be noted, these problems can add up to significant error if not properly accounted for. However, the situation can be improved by taking more data into account and learning more about how to properly interpret signals, said Kumar. 

Technologists and medical experts both know that getting this right—or as close to right as possible—is crucial. They also know that the technology will be a complement to the kind of manual contact tracing that epidemiologists have relied on for the last century: people talking to people and tracking disease through one-on-one conversations.