The Great Coronavirus Contact-Tracing Race

It starts with a phone call. You may have been in contact with someone who has coronavirus, a kind-sounding voice tells you: You should self-isolate and get tested for Covid-19, if possible. The caller is careful not to reveal the identity of the infected individual you’ve crossed paths with; if they’re good at their job, they’re sensitive both to your fears and the others’ privacy.

The voice on the line is a contact tracer — a person trained to track down and notify all the people who might have been exposed to coronavirus by someone who’s known to have the infection.

Contact tracing is being pursued as a key part of the global effort to target Covid-19 hot spots, slow the spread of infection, and reopen local economies. Most experts agree that to truly halt the disease, it will take far more widespread testing and, ultimately, an effective vaccine. But by carefully following the movement patterns of the human disease vectors that carry it, jurisdictions hope to be able to target their lockdown measures at individuals who are most at risk, allowing a semblance of normal public life to resume.

To safely reopen, the U.S. might need to train and deploy at least 100,000 contact tracers. But some hope that this laborious process could be at least partially automated. Tech companies are jockeying to introduce infection alert systems, which use phone data to do some of the legwork of tracking recent contacts. Apple and Google have teamed up to develop a tool that uses Bluetooth to identify which other devices (and the people who own them) you come close to each day; if someone gets sick, anonymous signals go out to the people that had entered their orbit, urging them to quarantine or stay home.

Outside the U.S., such tracing technology is already in the field. South Korea’s much-talked-about coronavirus control regime leans heavily on the smartphones that 95% of residents carry; authorities can piece together and share anonymized routes of potential carriers using location data, credit card records, and security tapes. The U.K.’s National Health Service is introducing a Bluetooth tracking app akin to Apple and Google’s; since it became available to the 800,000 residents of the Isle of Wight last week, in April that only about half of the tracers’ subjects pick up the phone, Ryan told me she’s surprised at how receptive people have been to her cold-calls.

“Everyone has been super willing to talk and answer questions about like, whether they had diarrhea or not,” she said. “People also seemed to be pretty willing to help out, because [they know that] part of the reason we’re collecting info on symptoms is to help better understand how it presents in different people.”

There’s no app for this

The interpersonal skills required to build this relationship is one reason why public health experts are skeptical about using technology to replace manual tracers.

“The human element of contacting someone on the phone, gaining their trust, having them view you as an ally, and accepting your recommendation to self-quarantine and share who they’ve had contact with is very important and somewhat of an art,” said Waters. “I’m not sure a tech-based solution could replicate that.”

Early in the coronavirus outbreak, Singapore’s contract tracing efforts were singled out for praise by the World Health Organization. The city-state of nearly 6 million acted aggressively to contain the virus, supplementing its vast network of human tracers with a tracing app, TraceTogether. But since its March launch, only a fifth of its residents has downloaded it, and Singapore has more recently experienced a surge in cases. New outbreaks have been sourced to dormitories where migrant workers lived, where Welty says it’s unlikely such an app would have helped; Singapore’s human army stepped in instead.

Oxford University researchers suggest that a minimum 60% adoption rate is necessary for a tracing system to be effective. Of all the countries using technology as a tracing supplement, MIT Techology Review found that Iceland’s app has the highest adoption rate, at 38%. For the country of 364,000 people, which has largely managed to flatten its curve, the app “wasn’t a game changer,” an official overseeing tracing efforts told MIT.

Jason Bey, the product lead for Singapore’s TraceTogether app, put it even more simply in a Medium post: “If you ask me whether any Bluetooth contact tracing system deployed or under development, anywhere in the world, is ready to replace manual contact tracing, I will say without qualification that the answer is, No.”

The prospects of a tech fix may be even dimmer in the U.S., where  privacy concerns are more widespread. Based on polling by the Washington Post and the University of Maryland, many Americans don’t trust tech companies with their public health information, despite assurances from the companies that they won’t save location data or store it in a centralized location. Three in five respondents reported being “unable or unwilling” to use such a system, and most expressed a greater trust in public health departments than Big Tech. Of people who owned smartphones, only 41% said they’d be willing to download the app.

That hasn’t stopped the emerging patchwork of coronavirus-tracing apps that are appearing at the local and state level, BuzzFeed News reported, which could introduce new incompatibilities between health departments and further scuttle any sort of coordinated national response.

Adding to the challenge, many communities especially vulnerable to the virus in the U.S. — migrant workers, people experiencing homelessness, and undocumented immigrants — do not have access to an internet-connected device, says Welty. They also might have more reason to hesitate before sharing movement patterns with an entity that they fear could pass them along to the government.

Even if an app was capable of locating potential contacts and asking the same series of automated questions, certain subtleties can’t be replicated, as when Welty carefully probes her subjects to try and determine when the contact happened. And a human tracer can also provide additional public health information, she says. For example, if a subject is told to stay inside but responds that they have to keep working to provide for their family, Welty submits their name and address to the city, which sends them food, cleaning supplies, or even diapers.

“We really need to be able to provide the services they need to isolate,” she says. Acts of support like this can help build trust among whole neighborhoods, like the communities of Latino San Franciscans Welty works with, who are testing positive at far higher rates than white residents.

“People also need guidance about where to get resources, how to communicate with their employers; some people fear loss of income or job,” said Dr. Emily S. Gurley, an infectious disease epidemiologist at the Center for Global Health at the Bloomberg School, in a press conference. “At the end of the day, this endeavor is about helping people in a difficult and scary time.”

But technology can be an effective ally in the Covid-19 battle. For those willing and digitally able to opt in, apps can be used by patients to record the results of daily temperature checks, or alert public health departments of their need for services, Braunstein said. And tracers like Ryan could use the assist when hunting down cold leads. Most of the people she’d contacted during recent shifts had been tested three weeks prior, which made remembering and finding the people they’d seen while developing symptoms much harder. One woman’s office used internal CCTV footage to help retrace her steps as soon as they knew she tested positive, Ryan said. By the time Ryan called, the brunt of the tracing work had already been done.

A lot has changed since the Ebola outbreak of 2014, when contact tracers in west Africa sat in centralized call centers or went door-to-door to find subjects. Today, technology can continue to push the craft forward, even without tying your health data to your GPS coordinates. “There are many ways that tech can support the public health function: It can help them be faster, it can help them organize data, it can help cases and contacts respond in a quick way about their signs and symptoms,” said Gurley. “Technology can be a support all along the way. But it never supplants the public health function.”

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