The first app using Apple and Google's COVID-19 contact tracing tech in the US is about to launch

• Apple and Google's contact tracing technology will make its US debut this week with the launch of Virginia's state-wide coronavirus contact tracing app.
• The technology uses Bluetooth on iPhones and Androids to detect other devices nearby and warn people if they've come in contact with someone who previously tested positive for COVID-19.
• Apple and Google's contact tracing tech has seen slow adoption since it was first rolled out in May, but the companies now say that 20 states have expressed interest.

The first COVID-19 contact tracing app in the US to use technology from Apple and Google will debut this week when the state of Virginia rolls out its "COVIDWISE" app.

Apple and Google have been building technology since April that would allow government health agencies to launch contact tracing apps that run smoothly on iPhones and Androids. The technology makes use of smartphones' Bluetooth sensors to detect when someone comes in close contact with a person who tested positive for coronavirus and alert them to get tested.

Virginia's app will use Bluetooth tracing without collecting any other data — like GPS location or personal information — in order to protect users' privacy, according to Virginia Public Media.

"No location data or personal information is ever collected, stored or transmitted to VDH as part of the app," a health department official told the outlet. "You can delete the app or turn off exposure notifications at any time."

The technology from Apple and Google, first rolled out in May, saw slow adoption by states at first — Business Insider reported in June that only three states had plans to use the technology. But since then, uptake has gradually increased, and Google said last week that 20 states are "exploring apps" based on the technology.

Contact tracing apps still face major hurdles before they'll prove effective. Public health experts estimate that 60% of a country's population need to participate in contact tracing apps in order for them to work, a threshold that many countries have struggled to attain. Singapore was one of the first countries to roll out a Bluetooth contact-tracing app in March, but saw only about 20% adoption. COVID-19 cases spiked in the country despite the app's rollout.

Another hurdle is interoperability — different apps made by neighboring states need to be compatible to prevent outbreaks among those who cross state lines. More widespread adoption of the Apple-Google technology could help with this, since apps using their technology run on the same Bluetooth protocol.

A more fundamental obstacle is the limited scale of testing in the US, which could mean many unreported cases of coronavirus. If people aren't able to quickly find out whether they have COVID-19, their use of contact tracing apps wouldn't make much of a difference to public health.