Apple and Google launched software Wednesday that will allow public health authorities around the world to create mobile applications that notify people when they may have come in contact with someone who’s been diagnosed with the coronavirus.

The effort, which the two tech giants call an “exposure notification” tool and utilize Bluetooth radios within smartphones, will be part of a new software update the companies will be pushing out Wednesday. State and federal governments can use it to create contact tracing apps that citizens can download via Apple’s App Store or the Google Play store. People who have updated their phones with the latest software will be able to share their Bluetooth signal, logging when the radio recognizes other people who have downloaded an app that uses the software.

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Apple and Google said some US states and 22 countries would be using the software, but the companies declined to provide a list of all the government agencies using it.