TOKYO >> The Japanese government has developed a contact-tracing smartphone app that will send notifications to users who may have come in contact with people hit with the coronavirus. Officials hope the app, touted as minimally intrusive, will be widely adopted.

Using technology co-developed by Apple Inc. and Google Inc., the app automatically exchanges Bluetooth signals between users, then sends “exposure notifications” to those who have been in close contact with people who test positive for COVID-19.

Unlike some versions outside Japan, the app does not harvest such personal information as a person’s name, date of birth, location or phone number.

The hope is that the app’s high level of privacy will make it palatable to the public.

The technology is meant to be a preventive measure against a second wave of infections after the nation completely lifted its state of emergency last week.

Prime Minister Shinzo Abe described the contact-tracing app as “key” to identifying and stamping out virus clusters, and called for its widespread usage.

The way the system works: A user’s smartphone will obtain and preserve encrypted codes of other users when they are within 1 meter (3.28 feet) of each other for more than 15 minutes.

If a user later tests positive for COVID-19 and confirms his status on the app, users who have come in contact with him in the previous 14 days will be notified.

Experts say a 60% participation rate is necessary to make the app effective.