Digital tools could speed tracking of coronavirus

A man wearing a face mask to help protect against the spread of the new coronavirus walks on the underpass in Seoul, South Korea, Thursday, April 2, 2020. For most people, the new coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia. (AP Photo/Ahn Young-joon)

Every strategy for releasing COVID-19’s vise-grip on daily life starts with identifying cases and tracing their contacts — the laborious task of public health workers tracking down people who have crossed paths with a newly diagnosed patient, so they can be quarantined well before they show symptoms.

That typically takes three days per new case, an insurmountable hurdle in the United States, with its low numbers of public health workers and tens of thousands of new cases every day. Existing digital tools, however, using cellphone location data and an app for self-reporting positive test results, could make the impossible possible, the authors of a new analysis argue.

“Traditional manual contact tracing procedures are not fast enough for [the new coronavirus],” researchers at the University of Oxford write in a paper in the journal Science this week. But digital technology "can make contact tracing and notification instantaneous.”


The “technology to the rescue” idea has been gaining steam as the coronavirus pandemic has outpaced everything Europe and the United States have thrown at it, and not because of a deluded belief that digital tech can solve all the world’s woes. Instead, this fix is aimed at identifying cases of COVID-19 and quickly tracing everyone who came into contact with them before they infect others. That has helped countries such as South Korea, Taiwan, and Singapore beat back the epidemic, though sometimes through measures that trample privacy.

Get Today's Headlines in your inbox:
The day's top stories delivered every morning.
Thank you for signing up! Sign up for more newsletters here

“We have evidence that this works,” said computational epidemiologist Maia Majumder of Boston Children’s Hospital, referring to contact tracing and case isolation. “The public health consensus is clear that this is what we need to do.”

The United States and Europe have hardly attempted contact tracing, however. It requires an army of public health workers or intrusive policies that many citizens oppose. But this week brought efforts to circumvent both obstacles.

One high-profile effort is led by Trevor Bedford, an infectious disease modeler and genomics expert at the Fred Hutchinson Cancer Research Center in Seattle. He and his colleagues have launched NextTrace, a project based on the fact that traditional contact tracing doesn’t scale: With more than 200,000 US cases and each case requiring hours of detailed follow-up, doing this by analog methods won’t work.

“So much of this virus’s transmission, maybe 15 percent of total cases, is from people who don’t feel sick,” said mathematical biologist Lauren Ancel Meyers of the University of Texas Austin, who is advising NextTrace. “And it’s spreading so quickly, with as few as four days from when one person shows symptoms to when people he infects does."


NextTrace plans to build a decentralized reporting system in which anyone with confirmed coronavirus can choose to register, anonymously, on an online platform. The platform will use cellphone location and proximity data from people who have opted in to find individuals who might have been exposed and advise them to be tested.

Basically, person A’s positive coronavirus test result would trigger an instant notification, again via the app, to individuals who have been in close contact. The platform would recommend isolation for that individual and quarantining of their contacts. The NextTrace team doesn’t specify if the information would be shared with public health departments, or how soon the system might be up and running.

Since this approach can “scale massively, it could significantly affect an epidemic even after there is widespread community transmission,” Meyers said. The information on the number of exposed contacts would also allow for better targeting of containment policies, with greater or less social distancing depending on the intensity of community spread.

With the instantaneous tracing promised by digital technology, said Oxford’s Luca Ferretti, an expert in pathogen dynamics and the first author of the Science paper, only 60 percent of cases would have to be isolated and 60 percent of contacts traced — and possibly as few as 50 percent and 40 percent, respectively.

People should have the right to participate or not, both the NextTrace and Oxford researchers say. If uptake is too low, however, the digitally enabled instantaneous tracing wouldn’t find enough contacts to stop an epidemic.


A similar platform could serve as an early-warning system for the next outbreak of COVID-19, which may well return later this year even if it fades in the summer. With fewer cases, the level of testing is likely to be even lower than it is today. That risks putting the United States exactly where it was this winter: with COVID-19 already seeded in a few cities and being spread undetected until it was too late.

“We’d like to identify regions where testing might not be happening and bring it to the attention of health authorities,” said Olivier Elemento of Weill Cornell Medicine, who before the coronavirus epidemic used big data for precision medicine.

Using a tool he and his colleagues built, people can anonymously report symptoms and where they live. It doesn’t collect IP addresses or otherwise track users. “But if we identify new clusters we will let states, counties, and cities know about them,” Elemento said, “so they could increase testing in those areas, put stricter social distancing in place, and alert local hospitals to a potential surge in patients.” A group at Boston Children’s Hospital and Harvard is developing a similar tool, as is one at the University of Alabama Birmingham.

Sharon Begley can be reached at [email protected]