Many countries and researchers are promoting the use of contact tracing apps to help limit the spread of COVID-19 and aid in the eventual recovery, but they may require slow manual tracing or a sacrifice in privacy (say, warning when a patient leaves home). MIT researchers think they have a solution with few compromises. They’re developing a system, PACT (Private Automatic Contact Tracing), that promises to automatically trace contacts while keeping identities secret.
The system would send Bluetooth “chirps” of random numbers to nearby phones. If a person tests positive for COVID-19, they can upload all their received chirps from the past 14 days (about the maximum incubation time) to help others find out if they were close by. If there’s a match between numbers, the passers-by get notifications telling them of possible contact and what to do next. The very nature of the process continuously changes IDs, making it difficult or impossible to link data to a given individual. There’s no GPS, phone numbers or other information people could use to guess who you are.
This is still a research project, and might require talking directly to phone OS developers like Apple and Google to implement properly. It does work cross-platform, though, and MIT is also showing its system to US federal and state governments.
If PACT can be ready in a timely fashion, it could be useful not just for minimizing the spread of COVID-19 during the outbreak, but play a vital role during the recovery. When lockdowns start lifting, an automated system like this could help keep public spaces open by asking people to quarantine only when they’ve recently been close to an infected person. Of course, this also requires widespread adoption to work — it would have to be an integrated, mandatory part of the OS to ensure that the right people know to isolate themselves.