Washington state Gov. Jay Inslee along with the Washington Department of Health announced on Monday the launch of what they call a “simple, anonymous exposure notification tool to help stop the spread of COVID-19.”

According to a press release, “WA Notify” is a smartphone app that will alert Washington residents if they spent time near another Notify user who later tests positive for COVID-19. The release also says the app uses “privacy-preserving technology and works without collecting or revealing any location or personal data” and is developed by Google and Apple.

“Secure, private and anonymous exposure notification technology is an important tool for Washington,” Inslee said. “We’ve deployed WA Notify in 29 languages so as many Washington residents as possible can protect themselves, their loved ones and their communities. I encourage everyone to start using WA Notify today so we can continue to work together to contain this virus.”

Data models for three Washington counties — King, Pierce and Snohomish — in found that COVID-19 infections and deaths could be reduced if even a small percentage of people enabled WA Notify and that the more users there are the more effective it is.

In the study, titled “Modeling the combined effect of digital exposure notification and non-pharmaceutical interventions on the COVID-19 epidemic in Washington state” conducted by Google Research, the University of Oxford’s Nuffield Department of Medicine and the Stanford University School of Medicine, researchers found that:

“Unsurprisingly, the effect on the epidemic is more significant at higher levels of app adoption. An app with 75% adoption reduces the total number of infections by 56-73%, 73-79%, and 67-81% and the number of total deaths by 52-70%, 69-78%, and 63-78% for King, Pierce, and Snohomish counties, respectively. Even at a relatively low level of adoption of 15%, total infections are reduced by 3.9-5.8%, 8.1-9.6%, and 6.3-11.8% and total deaths are reduced by 2.2-6.6%, 11.2-11.3%, and 8.2-15.0% for King, Pierce, and Snohomish counties, respectively.”

In general, the study stated, the higher the level of exposure notification adoption the greater the number of total quarantine events, with the exception of very high levels of adoption (60% and 75%) where this number plateaus or even decreases, likely due to the significant effect of the intervention in suppressing the overall epidemic in those scenarios.

“WA Notify complements the actions Washington residents are already taking, like wearing masks, physical distancing and keeping gatherings small,” WA Secretary of Health John Wiesman said. “We’re excited to be joining the states already using this safe and secure technology and encourage all Washingtonians to join the effort.”

The free and voluntary app uses Bluetooth technology to exchange random codes with the smartphones of other nearby users without revealing the user’s identity or location. Users who later test positive for COVID-19 can then voluntarily enter a verification code provided by public health into the app. WA Notify will then alert other users that have been near them within the past 14 days. User who may have been exposed will receive links to information about what to do to protect themselves and others in case they have contracted COVID-19.

WA Notify is available for both iPhone (enabled through iPhone settings) or Android (download the app through the Google Play store) and users can opt out at any time.

University of Washington Computer Science and Engineering Associate Professor Stefano Tessaro addressed concerns the app would be used for contract-tracing purposes.

“People are understandably concerned these days about being tracked and having their personal information compromised,” he said. “However, the technology behind WA Notify has been vetted by security and privacy experts across the world, and it does not collect or store any information that personally identifies its users. I plan to add WA Notify to my phone and I will encourage my friends and family to use it as well.”

According to the press release, Colorado, New York and Virginia are using the tool as is Canada, Germany and Ireland.

The release states that before launching the app, the state “received a recommendation to adopt the technology from an oversight committee which included security and civil liberties experts and community leaders representing communities of color, individuals with disabilities and other communities disproportionately impacted by COVID-19.”

University of Washington’s schools of computer science, medicine, public health and nursing, as well as support from the Brotman Baty Institute also contributed to the app. UW also tested WA Notify with students during the month of November to help inform a statewide roll-out.

For more information, visit WANotify.org.