What it needs to work

Rival tech giants Google and Apple have teamed up to create technology to help health officals trace who’s been infected by Covid-19, and are building it directly into iOS and Android, the two operating systems that power almost 100% of the world’s smartphones. 

It’s a big announcement — not only is it an unusual example of two tech giants working together, but digital contact tracing is a technology that is being closely watched to see if it can help schools and businesses re-open when the Covid-19 coronavirus epidemic slows down.

It’s a digital version of traditional contact tracing, a labor-intensive process in which public health officials contact everyone who might have been exposed to someone infected with Covid-19 to tell them to self-isolate or get tested.  Contact tracing is a big part of mitigation efforts in Hong Kong and Taiwan, for example. 

In its digital form, Apple and Google are making it possible to automate this process at large scale by giving public health authorities the ability to tell when people are near each other by using signals picked up from their smartphones.Those tools will become available through iOS and Android operating systems in mid-May, the companies say. Both companies are emphasizing privacy, saying that the tools won’t identify particular individuals, but will only make it possible for public health officials to contact people who might have been exposed.

Officials in the United States say that massively expanding contact tracing is a key step in order to make it safe enough for governments around the world to allow gatherings and for people to go back to work. CDC Director Robert Redford told NPR in April that “very aggressive” contact tracing will be required for the U.S. to return to normal. 

“Control measures can only be lifted if the right public health measures are in place, including significant capacity for contact tracing,” World Health Organization director general Dr. Tedros Ghebreyesus said this week.

But digital contact tracing is not a magic bullet, and there are a lot of steps that still need to happen before digital contact tracing apps start slowing the spread of the coronavirus around the world. 

First, the apps themselves need to be built.

Apple and Google are only making the technology available and easier to implement — it will be up to official health groups that would normally do contact tracing to actually build and distribute the apps. (Official groups are the only organizations that can access the APIs Apple and Google are building.)

Google and Apple say they will provide support organizations building these apps, and even provide sample apps that they can use as a starting point. But health organizations around the world vary in their technical sophistication, privacy regulations, and amount of institutional attention they can offer at the moment, and when the apps become available will likely vary by region. 

Google and Apple’s APIs will become available in mid-May in software updates, the companies say. Britain’s National Health Service, among others, is already working on an app. But no release dates or launch plans have been confirmed yet. 

When the apps are available, they will require testing to be readily available.

The way the proposed apps work, if someone tests positive for Covid-19, the apps will be able to use Bluetooth to figure out all the other phones that they’ve crossed paths with in the past few weeks and ping them. Cryptography will be employed to make sure that the apps can’t identify individuals on either end.

But if anyone can say that they believe they’re Covid-19 positive without independent verification, it opens the system to false notifications and other trolling. Apple and Google both confirmed that the apps will only be triggered when there’s a verified positive test.

So for digital contact tracing to work, there need to be enough Covid-19 tests for anyone who believes they’re positive. In the United States, over 3 million test have been performed so far, according to the COVID Tracking Project. But officials still say there is still a lack of testing kits, and some experts say that there needs to be millions of tests done per day. 

Users will actively have to participate, or “opt-in,” to use the apps and systems built with the Google and Apple technology, according to company representatives. Users will have to download an app or, later this year, consent through a pop-up to participate in helping public agencies track Covid-19 cases. Governments won’t be allowed to mandate usage, the companies say.

That means everyone who participates will need to consent to share their location and proximity data. 

The more people that use the system, the more effective it will be. One estimate from a contact tracing research group suggests that 60% of people in a region would need to download an app before digital contact tracing could stop the spread of the virus. Apple and Google representatives say the more people that use digital contact tracing the more effective it will be, but have not mentioned a benchmark they’re shooting for. 

In technical communications, Apple and Google have made clear that the technology they’re releasing won’t give them a new database of user locations — in fact, it doesn’t use GPS location data at all — but there’s evidently still a lot of convincing to do on the privacy front, at least in the United States. 

Sen. Richard Blumenthal said on Wednesday in a statement that “Apple and Google have a lot of work to do to convince a rightfully skeptical public that they are fully serious about the privacy and security of their contact tracing efforts.” President Trump praised Apple and Google’s initiative on Tuesday, but warned that it would raise “big constitutional problems” for “a lot of people.” 

Digital contact tracing never been practiced at a global or national scale, and there are still questions about how well the technology works.

For example, Singapore is one of the countries with an existing digital contact tracing app, although it does not use the Apple and Google protocol. But Jason Bay, one of the technologists who wrote the TraceTogether app, expressed reservations about the technology in a blog post last week, suggesting that contact tracing apps work best in conjunction with human-led interviews. 

“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,” Bay wrote. 

In addition, manual contact tracing is essential for demographic groups, such as minorities, that may not trust authorities or may need help navigating the medical system, said David Harvey, Executive Director of the National Coalition for STD Directors.

“We’re not opposed to digital contact tracing. We should have done this 10 years ago, but it’s difficult to ramp this up overnight and the companies can’t just unleash all this new technology and new hires and reach people who mistrust the system,” Harvey said.

The CDC-funded group has historically done contact tracing for STDs and other infectious diseases before the Covid-19 pandemic. The majority of the group’s 1,600 “disease investigation specialists” have been redeployed to Covid-19 efforts, but the country would be smart to hire more and better utilize existing resources which already engage in contact tracing practices, Harvey said. 

“Nothing replaces boots on the ground and a workforce trusted by local communities,” he added.