Did you get a COVID-19 warning from California’s phone app? Why you probably didn’t
Late last year, California asked its residents to do a remarkably altruistic thing: Tell a state-sponsored cell phone app if they’d tested positive for COVID-19, as a public service to save lives.
The app, called CA Notify, would send other users who’d come in contact with the infected person an alert saying they’d been exposed within the past 14 days — perhaps in the workplace, grocery store or coffee shop.
So far, though, the results have been underwhelming. Californians may be less altruistic than hoped.
Although 9.5 million people have signed up to receive notifications, only about 83,000 COVID-19-infected people have agreed to participate. It appears the people most at risk of spreading the disease are not going through the steps that would send an alert.
Hailed in December by Gov. Gavin Newsom as a sign of California’s “innovative spirit,” the app appears to have so far fallen victim to worries about privacy and the pervasiveness of surveillance technology, even though the system is anonymous and doesn’t collect tracking information.
Experts said the preliminary data from CA Notify shows a lackluster response, especially for such a tech-savvy state. About 100,000 people have received exposure alerts from the CA Notify app since it was released in December. During that same time, nearly 2 million new infections have been recorded in California.
But a university health official who runs CA Notify with the state Department of Public Health defended the results and said the numbers aren’t insignificant.
Dr. Chris Longhurst, chief information officer with UC San Diego Health, said about 1,000 people have received alerts each day, on average, and the refined technology will almost certainly prove helpful in future disease outbreaks.
“Unfortunately, I think some of the really good data on whether it actually is working, it won’t come until the pandemic is over,” said Longhurst. UC San Diego has a $2 million contract to work with the public health department on the program.
He said administrators are working on ways to boost the program’s use after someone tests positive.
When The Sacramento Bee first asked the California Department of Public Health for data about alerts, a spokesperson said the agency couldn’t provide details “due to the privacy-preserving design.”
Officials later said that the security features within the program make it impossible to know precisely how many notifications have been sent. Instead, they make estimates based on how many times someone ends up on a specific webpage after clicking a link about the exposure notifications.
The extreme privacy concerns have users in mind but have admittedly made it difficult for program administrators to track its effectiveness. It’s unclear how many of the 100,000 notifications went to people who were previously unaware of being exposed and how many, for example, went to family members in the same house as an infected person.
“We have anecdotal information that it’s working. We see that people are launching exposure notifications. We know that people are testing because they got exposure notification,” Longhurst said. “So I think it’s accomplishing our goals.”
Sacramento-area health officials don’t know how many alerts have been sent.
“There has been no involvement. Sacramento County does not have integration with the state on this technology,” Brenda Bongiorno, a county spokeswoman, wrote in an email.
Privacy in mind since the beginning
The intense privacy is intended to quell criticism throughout the pandemic that private testing data could fall into the wrong hands. The app does not track a user’s location, nor does it share a user’s identity. It uses Bluetooth technology to exchange random codes between users’ phones. If a user tests positive, they enter a verification code into their phone app and it notifies potentially exposed people.
Nonetheless, the app might be making some Californians uneasy about having their privacy compromised.
“People are concerned about their own privacy; there are folks who are extremely hesitant or absolutely will not use this technology,” said George Usi, founder of Omnistruct Inc., a cybersecurity company based in Rancho Cordova.
Riverside attorney Glen Price, a cybersecurity specialist at the Best Best & Krieger law firm, said privacy concerns likely become heightened when people test positive and are about to enter the required verification code in their phones to trigger alerts.
“It may be at that point that people get nervous,” Price said. “There’s the concern that … someone’s going to find out you’re COVID-positive and that’s a mark of shame.”
Price said it appears the app developers did everything they could to ensure users’ privacy but “it’s hard to convince people. That’s been a huge problem with all of these apps. People don’t trust them.”
Yet a similar system in the United Kingdom warned more than 1.7 million users across England and Wales, the U.K.’s National Health Services reported last month. The app has now been downloaded 21.6 million times, representing 56% of the eligible population.
Contact tracing apps like CA Notify were never going to be a “magic bullet,” said Dr. Isobel Braithwaite, a researcher at University College London who has studied similar contact tracing programs. But California’s early results don’t mean the app isn’t working as intended — they just mean not enough people have been using it.
The app’s limits come down to basic math and human behavior. Even with some 9.5 million activations, the chances are slim that two people with charged phones and activated apps would spend 15 minutes within 6 feet of each other.
“That’s why the modeled benefits are much greater at higher levels of uptake,” she said.
In California, the lackluster reception to CA Notify wasn’t totally unexpected.
“I’m very, very sober about the adoption rate and I don’t expect tens of millions of people. Quite the contrary,” Newsom said Dec. 7. “We are hoping that there will be enough to make this meaningful.”
Though the program came relatively late in the pandemic, and was soon pushed out of news cycles by vaccine talk, about 37% of eligible cell phone users in the state are thought to have registered, on par with similar efforts in other states.
Longhurst said about nine times as many people have enrolled in CA Notify on an iPhone, which merely has a pre-installed opt-in setting, compared to Android, which requires users to actually download an app.
That’s significant because Apple users tend to be more affluent and more likely to have jobs that allow them to safely work from home and avoid exposures in the first place. Android users are more likely to work and live in places more at risk.
Are guidelines too strict?
There’s also the question of what counts as a COVID-19 exposure in the first place.
CA Notify only alerts when someone who has a positive test was believed to have been within 6 feet of someone else for at least 15 minutes. It’s based on CDC guidelines.
You wouldn’t get an alert from brushing up against someone in a grocery store line, sitting next to someone on a short bus ride or even coming across an infected person briefly in a hospital waiting room based on those guidelines.
“It’s basically occupational exposure,” said Andrew Noymer, an epidemiologist and associate professor of population health at UC Irvine.
Noymer said it was impressive that so many people activated or downloaded the app. He didn’t fault the state for trying but said it “was not a game-changer.”
“It should be a cautionary tale for how far we’re going to be able to ‘tech’ our way out of the pandemic,” Noymer said. He has the app himself but has never gotten an alert, he said.
For the app to work, users must realize the link is not a scam, click it and go through the steps to launch the notifications. But someone who just received a positive test likely has other things on their mind, marking yet another barrier.
Longhurst said the potential for phone-based disease alerts is clear. It could even be helpful during flu season or the next respiratory pandemic. Contact tracing has worked well for decades in tracking exposure to sexually transmitted diseases. But it is labor-intensive detective work ill-suited for a fast-spreading respiratory pandemic, like COVID-19.
“You can remember who you were intimate with,” Longhurst said. “People can’t remember who they breathed air with. And that’s where a technology like this could become really awesome.”
This story was originally published March 15, 2021 at 5:00 AM with the headline "Did you get a COVID-19 warning from California’s phone app? Why you probably didn’t."