New Crop of Covid-Tracking Apps Addresses Old Concerns

But apps using Apple and Google technology may raise the bar by using Bluetooth to more accurately compile users’ close encounters with other phones, with no location-tracking at all.

Still, any of these new apps faces difficulties from the start, said Jenny Wanger, head of the Implementor’s Forum at the Linux Foundation Public Health, a nonprofit that provides software and assistance to agencies working on exposure notifications. Those problems include convincing people that the apps are effective in deterring coronavirus, and then getting the explicit permissions the apps need to function.

“As time goes by, we found it’s not just about designing a good app,” Ms. Wanger said. “It’s about designing a go-to market strategy that’s going to be productive.”

Apple and Google weren’t involved in these apps’ development, but did set guidelines for use of their technology. The apps now making use of it are trying to engage users through a mix of strategically prominent disclosures, coupled with deliberately limited features.

Privacy First

Mindful of privacy concerns, some apps open with a barrage of detail on what information they collect and what they don’t, in an effort to reassure users.

For instance, Covidwise, introduced Aug. 5 in the commonwealth of Virginia, presents users with three text-heavy screens on privacy, notifications and the importance of sharing test results before the user ever sees the app’s home screen. (That is the opposite of what usually happens: app developers generally try to drive users straight into the main experience, with a minimum of preamble.)

But Virginia gambled that emphasizing privacy would encourage use, said Andrew Larimer, a developer at SpringML Inc., which created the app with Virginia’s Department of Health.

“One of the primary concerns is how much information can we provide to help users understand the system as clearly as possible so they can feel good about using it and understand it’s protecting their privacy,” Mr. Larimer said.

Some other apps have adopted the same approach, such as GuideSafe from the University of Alabama at Birmingham and Covid Trace from the Nevada Department of Health and Human Services.

Bits of Personalization

In Arizona, authorities worked with the nonprofit group Covid Watch to create a contact-tracing app designed for three different pools of users: people at the University of Arizona and Northern Arizona University, and people in Arizona in general. When the app notifies users they have been in proximity to someone who tested positive for coronavirus, it tailors recommendations according to the apparent risk. For instance, it may recommend staying home for a few days rather than a full 14-day quarantine if the exposure was relatively far in the past.

It is partly an effort to be realistic, said Sameer Halai, co-founder and head of product at Covid Watch, which released its eponymous app on Aug. 19. A user who gets two exposure notifications in a month might resist quarantining 14 days each time, he said.

“This is just yet another way that we are able to get through to someone we otherwise wouldn’t be able to,” Mr. Halai said.

In North Dakota and Wyoming, Care19 Alert was introduced Aug. 13 by ProudCrowd LLC. Like Covid Watch, it offers a level of personalization: people can add a university or business affiliation to get recommendations specific to their school or employer. Those institutions can define the proximity and length of contact that counts as an exposure for their populations, ProudCrowd said.

Care19 Alert also includes a tab showing how many times it has checked to see if the user was potentially exposed to Covid-19, mimicking a common element of antivirus software that regularly displays the results of its sweeps. The idea is that once users know the app is constantly updating, they might begin to stay on top of it. Care19 Alert checks for exposures about every six or seven hours, ProudCrowd says.

Will the Apps Ever Talk to Each Other?

Even so, the apps take a piecemeal, regional approach to what is a global pandemic. As they proliferate, their ability to communicate with each another becomes more important, said Ms. Wanger of Linux Foundation Public Health.

At present, most states’ apps only trigger exposure notifications for people using the same app. And there is no overarching national contact-tracing app in the U.S.

Whether the new apps will be used broadly enough to meaningfully slow the virus is unclear. But they are getting enough traction locally—Covidwise has been downloaded over 535,000 times in Virginia, Covid Watch about 26,000 times in Arizona and Care19 Alert around 10,000 times in North Dakota, according to their developers—that interoperability is the next frontier.

In July, the Association of Public Health Laboratories, a trade group, announced a joint effort between Google, Apple and

Microsoft Corp.

to enable interoperability through a national server, though only apps that use Google and Apple technology will be able to participate.

But Google and Apple this month announced a workaround that might expand the geographical reach of electronic contact-tracing: Exposure Notifications Express, an update to their Bluetooth technology that could make it simpler to get notifications.

Apple will let users opt in without an app and will eventually send notifications, with phones, instead of only apps, communicating a possible exposure. States, however, must supply Google and Apple with information. Maryland, among others, plans to use the system.

People with phones running Google’s Android operating system will be able to use state-branded apps—this time generated by the company—with information from public health authorities. These apps might eventually communicate with sibling apps in other states.

Write to Ann-Marie Alcántara at ann-marie.alcantara@wsj.com