Cellphone tracking could help stem the spread of coronavirus. Is privacy the price?
by Kelly Servick March 22, 2020
“IT IS POSSIBLE TO STOP THE EPIDEMIC.” That’s the message splashed atop a website built by a University of Oxford team this week to share new research on the spread of the novel coronavirus. Below that hopeful statement comes a big caveat: To stop the virus’ spread, health officials need to find and isolate the contacts of infected people–lots of them–fast. Such contact tracing is a mainstay in infectious disease control. But the Oxford team is one of several now advocating for a new approach: tapping into cellphone location data to track the spread of infection and warn people who may have been exposed.
Several governments in Asia have tried that approach in ways that would run afoul of privacy laws in many other countries. China, for example, has reportedly relied on mass surveillance of phones to classify individuals by their health status and restrict their movements. Now, research teams in Europe and the United States are considering less invasive ways to collect and share data about infections, and some are already developing and testing coronavirus-specific phone apps. Governments, meanwhile, are scrambling to figure out how these potential pandemic-fighting tools could work within data privacy laws and without losing the support of an already wary public.
“We don’t live in a culture of public trust when it comes to data,” says David Leslie, an ethicist at the Alan Turing Institute who studies the governance of data-driven technologies. “We live in this age that has been called the age of surveillance capitalism, where…our data is abused and exploited.” But, he adds, authorities and the public will have to weigh the value of privacy against the possibility that data collection could save millions of lives. “These are not normal times.”
Behind in the chase
Tracing the people an infected person recently came near requires widespread testing to diagnose infections in the first place. That testing has been painfully slow to ramp up in the United States and parts of Europe–to say nothing of countries elsewhere with fewer resources. Even as more tests become available, state and local health departments may not be able to interview every patient and follow up with every contact. And even the most painstaking interview can’t reveal contacts or places that a person just doesn’t remember.
The virus that is causing the pandemic, severe acute respiratory syndrome coronavirus 2, poses a particular challenge, says Oxford infectious disease epidemiologist Christophe Fraser. So far, it appears that nearly half of transmissions happen before an infected person has symptoms. That means the virus can spread for days before health authorities even learn of a spreader. “No matter how many resources you put into [contact tracing], it’s never going to keep ahead of the virus,” he says. “It’s always going to be one or two generations ahead.”
Fraser and his colleagues have watched U.K. coronavirus cases climb in recent weeks while new cases in China plummeted. Two postdoctoral researchers in his lab described their families in China using a phone app that told them when and where it was safe to go out. “We thought, ‘Well, what would we do, if we [built] an app?’”
Fraser, with Oxford clinician David Bonsall and colleagues, designed a mathematical simulation of how “instantaneous digital contact tracing” would influence the spread of the virus. To stop the epidemic, health officials must reduce the virus’ reproductive number–the average number of people each infected person transmits the virus to–to less than one. When the team modeled a scenario in which contacts were notified the instant a person tested positive, it was possible to push the reproductive rate of the virus below that threshold, the team reported in a preprint this week.