OAKLAND, California: North Dakota, Wyoming and Alabama are the latest US states launching apps to warn users about potential exposure to the novel coronavirus by tracking their encounters, representatives for the states told Reuters on Thursday (Aug 13).
Virginia last week became the first US state to urge residents to download such an app using technology developed by smartphone software giants Apple and Alphabet's Google.
About 316,000 people have downloaded Virginia's app, COVIDWISE, Jeff Stover, a state health department official, told Reuters during an online event about pandemic technology hosted by the Massachusetts Institute of Technology-affiliated Responsible Data Foundation.
North Dakota launched its app, Care19 Alert, on Thursday and Wyoming will release an app on Friday, whose company ProudCrowd developed the apps, also said during the event.
Alabama, which has been testing its GuideSafe app among some university students and staff, plans to begin marketing it statewide on Monday, said Sue Feldman, director of graduate programmes in health informatics at University of Alabama at Birmingham.
Washington, which recently tested its CommonCircle app at a hospital, and Pennsylvania are among other states that could formally launch apps in the coming weeks with the Apple-Google technology.
The technology enables phones to exchange Bluetooth signals to keep an anonymous list of close encounters. A user who becomes infected can anonymously notify recent contacts to get tested or quarantine.
But developers acknowledge they still face challenges in convincing users that the tracking and notification systems are private and reliable.
For instance, getting contact tracing apps from different states to communicate with each other, as users cross borders, is untested with North Dakota's app now the first and only in the United States to support that functionality.
North Dakota previously released an app, Care19 Diary, to help users remember their location history for contact tracing.