Since it launched on Monday, more than 700,000 Washington residents have installed or activated the WA Notify app. The free smartphone tool sends out warnings if people have been potentially exposed to someone who tests positive for COVID-19.
“It is secure, anonymous and quick to set up,” tweeted Gov. Jay Inslee, in announcing the number of WA Notify users, which totals more than 9% of the state’s population. Update: More than 1.1 million people signed up for WA Notify in the first week, Gov. Inslee announced Friday.
But even as the rate of adoption climbs, will the exposure notification app make a difference?
Experts and officials worldwide aren’t so sure. The limited evidence that exists so far makes clear the apps aren’t creating a big dent in the spread of the virus.
However, given the U.S. recorded 1 million new infections in a week, many health officials are eager for whatever help they can get.
More than 700,000 people have now activated WA Notify – Washington’s COVID-19 notification tool.
It is secure, anonymous and quick to set up.
Join today ➡️ https://t.co/Zxnmwvumu4 https://t.co/Dsrc6gz7PU pic.twitter.com/marQ3FL9Kg
— Governor Jay Inslee (@GovInslee) December 1, 2020
WA Notify is built on technology developed by Apple and Google called the Exposure Notification System. The app uses Bluetooth signals emitted by smartphones to detect and remember interactions, allowing people to receive a message if they’ve been within six feet for at least 15 minutes with someone who later tests positive for COVID-19.
The app does not use GPS and does not indicate where the potential exposure occurred. It’s meant to compliment the manual contract tracing being done by workers who identify and inform people who’ve been in contact with someone infected with COVID-19. The digital system could catch exposures that occur in anonymous settings such as grocery stores, busses and airports.
Dr. John Wiesman, the state’s secretary of health, told GeekWire that the app is part of a toolbox “for Washingtonians to take control in their own lives to help keep them safe.”
Others remain skeptical.
“I’m getting asked whether people should turn on exposure notification on their phones. Go ahead. It’s not bad from a privacy perspective. It’s just unlikely to make you or anyone any safer,” Ryan Calo, a University of Washington law professor and privacy expert, tweeted on Tuesday.
The exposure notification system you built, while elegant from a privacy perspective, is useless. Please devote your considerable powers to designing a vaccine emoji that isn't likely to horrify everyone. ???
With thanks,
Ryan Calo
— Ryan Calo (@rcalo) December 1, 2020
COVID notification apps have a heavy lift. First and foremost, they need to protect individual privacy. To accomplish that, they’re limited in the information that’s being gathered and shared with users and health officials, which reduces their benefits. Norway had to scuttle its original contact tracing app because it didn’t do enough to safeguard individual privacy.
The app risks generating false positives because it can’t tell if people are masked or outside, reducing the likelihood of infection. People could be within six feet but have a wall or shield between them. It can miss actual cases if both parties don’t have both a smartphone and the app. Even if they do detect a possible exposure, people who test positive are encouraged, but not required, to send a warning to other app users and many don’t.
“It was never going to work because it’s as [likely] to be over- and under-inclusive as on target,” Calo continued in his tweet. “It’s lovely to think a magic app will keep you safe — but it won’t. And there’s no evidence it works even in places where it’s been mandatory.”
Yeah, privacy aspect is fine. But that’s also why I’m not turning it on. If I get an alert, I have no way of finding out if the supposed infected person is someone I was close to for a meaningful period of time. Am I going to quarantine on such opaque info?
— Martin Kaste (@MartinKaste) December 1, 2020
Headlines that cheer the success of the apps often focus on how many people have installed them, rather than epidemiological data showing they’ve made a significant difference. Experts say it will be difficult to quantify the impact of the apps. Washington health officials said they expect to receive aggregate data telling them how many notifications are sent.
Many proponents of digital warning apps point to an unpublished study that modeled the tool’s potential benefits for King, Snohomish and Pierce counties in Washington state.
The study by epidemiologists and modellers at Oxford University and Google Research predicted that if 15% of the population used the app that it would cut infections by 8% and deaths by 6%. Used alongside a “well-staffed manual contact tracing workforce,” the infections would be cut by 15% and deaths by 11%.
Experiences in Germany and Ireland provide some insight into adoption and performance of exposure notification apps, which both countries launched in July.
In Germany, roughly 22 million of the country’s 83 million people have installed the app. The government’s health agency website calls it “an important component of pandemic control,” but does not readily offer information to back the claim. In early November, health officials said that only 60% people who tested positive used the app to notify others, according to news reports.
In mid-October Ireland reported 1.3 million active users — roughly 34% of its population. More than 3,000 people had used the system to warn others, sending notifications to more than 5,800 people. In a press release Irish authorities did not share other details about the alerts except to say: “Some of these may not otherwise have been identified.”
