"We know people are contagious before they show symptoms. This can really help us catch new cases early before they spread as far," Northam said during a press conference on Wednesday.

COVIDWISE – which state officials stress is an "exposure notification" app, not an app for direct contact tracing – allows users to voluntarily and anonymously report positive COVID-19 test results, and alert other app users who've been near them, NPR.

Rather than tracking users' identity and location, Virginia officials say, the Bluetooth technology creates anonymous "tokens," or random sequences of numbers, and exchanges them with other nearby users, then the app uses that information to inform users if they've been near someone who has reported a positive test, reports NPR. 

The use of technology for contact tracing has raised privacy concerns. However, NPR notes that during a briefing earlier Wednesday, Jeff Stover with the Virginia Department of Health said officials chose to use the Bluetooth-based app, rather than location-based contact tracing technology some other states have used, in response to such concerns. "We can't do our job well if we can't ensure that the people that we're working with trust us to ensure the privacy and confidentiality of our data," Stover said. "We were very aware of that as we went into the development of this app."