More States Offer Covid-19 Contact-Tracing Apps, but Adoption Is Uneven

Exposure notification technology, now available to more Americans, shows promise

New York’s contact-tracing app has been downloaded roughly 700,000 times.

Photo: Mark Kauzlarich/Bloomberg News

Covid-19 contact-tracing apps from Apple Inc. AAPL -1.37% and Google are coming to more states, along with evidence that they can help slow infections as long as enough people use them.

Fourteen states and Washington, D.C., have recently adopted the “exposure notification” technology the companies built into their smartphone operating systems—Big Tech’s most significant contribution to the fight against Covid-19. California, and other states are piloting the technology and could release it soon. It lets people who have tested positive for Covid-19 alert others they have previously been in close contact with that they should take precautions or get a test.

As case counts explode and a nationwide rollout of vaccines remains months away, epidemiologists say the technology can help slow the virus’s spread—if widely used and fast testing is broadly available. Yet many of the millions of Americans who have access so far are skeptical, suspicious or simply unaware of it.

That has been the struggle in Virginia, which in early August became the first state to roll out an exposure notification app. Three months later, downloads of the app, known as Covidwise, amounted to roughly a 10th of Virginia’s population of about 8.5 million.

Politicization of the virus has hampered efforts to increase the app’s adoption, said Jeff Stover, executive adviser to Virginia’s health commissioner who is in charge of Covidwise. “That doesn’t help convince Virginians to download and run an exposure notification app that is run by the government,” he said.

Nearby Washington, D.C., offers some hope for public participation. A third of the district’s population, including commuters, had activated the smartphone function less than a month after it became available, thanks to a tweak from Apple and Google that allows public-health authorities to send push alerts that the technology is available. Colorado and Maryland also have seen fast uptake after sending push alerts.

Mr. Stover said Virginia plans an update in a few weeks so it can send alerts and allow Covidwise to work with versions of the technology being run elsewhere, including nearby Washington, D.C., and Maryland.

Many European countries rolled out apps based on the Apple-Google technology this summer. In Switzerland, 1,695 people called a special hotline after receiving a notification in the SwissCovid app that they had been exposed and 65 people who tested positive credited a notification from the app for encouraging them to get a test, according to a paper published in September.

Armin Betschart, an insurance executive who lives in a Zurich suburb, remembers a Monday afternoon in September when his SwissCovid app warned him of a possible exposure. The notification came a few hours before a family member called with news of a positive test, Mr. Betschart said.

He tested negative but believes if he had been positive, and the exposure came from a stranger, the app would’ve been his only warning that he might be contagious before the onset of symptoms.

A billboard in Times Square last month urged New Yorkers to download the Covid-19 tracking app to their phones.

Photo: Richard B. Levine/Zuma Press

Despite the promised benefits, few in the U.S. have downloaded the state-based apps or otherwise enabled the technology on their phones. About 800,000 people have downloaded Virginia’s app to date, Mr. Stover said. New York’s app has been downloaded roughly 700,000 times and Pennsylvania’s 500,000 times, according to data from research firm Sensor Tower.

If few people download the apps, their impact will be limited. With about 10% of Virginians using Covidwise, that means there is a 10% chance the people they bump into are using it as well, so only 1% of close contacts are theoretically logged, limiting the potential number of exposure notifications that can be sent.

“If I were to test positive, it would be good to know that I had a way to alert people that I have no way to contact directly,” said Kelly DeLucia, who lives in Yorktown, Va., and uses Covidwise. “I think that if we could reach critical mass with the number of users, it could be a real tool to help contain the spread.”

Virginia’s governor, Ralph Northam, has promoted the app at news conferences. When he came down with Covid-19 in late September, three of his staff members received alerts that they had been exposed. All three had been traveling with the governor, so they were aware of their exposure before receiving the smartphone alert, according to his press secretary, Alena Yarmosky, who was one of the three.

It was a real-world test that demonstrated the technology works, Ms. Yarmosky said, adding that it may have alerted others the governor came into contact with who didn’t know about his positive test.

Virginia rolled out the Covidwise app in early August.

Photo: olivier douliery/Agence France-Presse/Getty Images

Other Virginians say they are skeptical of the technology. Kellen MacBeth, who works from home in Arlington, said he sees why people in high-risk jobs might want to use the app, but he doesn’t see why he would need it since he didn’t leave his house for three months early in the pandemic and has since limited his contacts to a few close friends. He tries to avoid downloading apps to protect his privacy, he said.

The Virginia Department of Health can see how often Covidwise is downloaded, and it has sent 116 notifications a day, on average, since late August. But it doesn’t know who has been notified or where they live. That information could help public-health authorities direct resources to hot spots, but Apple and Google designed the system to obscure it to protect privacy, the companies have said.

Two local Virginia Facebook groups offer a glimpse of how opinions about Covidwise, much like masks, are split along political lines. One of the groups is for residents of Arlington County, which mostly supported Joe Biden, and the other for residents of Montpelier in Hanover County, which voted more often for Donald Trump. A post about Covidwise in the Arlington County group elicited mostly positive comments that the app could help stop the virus’s spread. A similar post in the Montpelier group drew more negative comments, suggesting the app would invade privacy.

Google and Apple say the technology protects people’s privacy. The companies posted the source code publicly so that claim can be verified, they say.

Some Virginians don’t use Covidwise because they aren’t aware of it. Each week, hundreds of grocery store cashiers, construction workers and others facing high risk show up to get free Covid tests at the Arlington Mill Community Center, where there were no signs promoting the app. A patient exiting the center after a recent visit told a Wall Street Journal reporter that staff didn’t mention it.

Mr. Stover said Virginia has a $1.5 million budget to promote Covidwise.

Apple and Google hope they can solve the problem of anemic adoption with a new release that lets states avoid the time and expense of developing their own apps and allows them to send push alerts directly to smartphone users to enable exposure notifications.

Washington, D.C., began sending out push alerts to residents and commuters on Oct. 20. By Nov. 18, 384,000 people, roughly a third of its workday population, had activated the technology on their smartphones. Maryland and Colorado also sent push alerts and have seen almost 20% of their population activate the technology within a month of launch.?

Wider adoption of exposure notification technology is of little use if other links in the chain break. Switzerland looked like a success story in early September, but that was before case counts jumped in October, said Marcel Salathé, head of digital epidemiology for the Swiss government’s Covid-19 task force. Mr. Salathé wrote a paper showing early, promising data for the SwissCovid app. Testing can take days and getting the code sometimes even longer, delaying notifications to the point of uselessness, he said.

“These systems can make quite a difference, if they are set up properly,” said Mr. Salathé. “It’s a shame when they aren’t given that chance.”


Would you be comfortable using an exposure notification app? Why or why not? Join the conversation below.

Write to Rolfe Winkler at

Copyright ?2020 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8