Contact Tracing: Behind Apple and Google’s effort against COVID-19

One of the best tools health officials have to slow down an infectious disease like COVID-19 is a technique called contact tracing. It involves health officials tracking individuals who have been in contact with people infected by the disease. This method is an efficient way of slowing the spread by finding and isolating cases.

Though efficient, contact tracing can be a slow process. Health officials have to interview the infected individual to learn about the places they’ve been to and people they’ve been in contact with. Depending on the context, they may also have to interview people in the patient’s social circle or anyone else who may also know of their contacts. The next step is to contact the people that have been in contact with the patient, warn them of the infection and what the next steps are.

With the worldwide spread of the COVID-19 pandemic, tech companies and governments are working together to accelerate and automate this technique. The first examples of this come from Asia, where the virus was first discovered and where it began to spread. The Chinese government, in partnership with Alipay, the largest mobile payment platform in the country, deployed an app used by citizens to check with they have been in contact with people diagnosed with COVID-19. Singapore has also deployed an app called TraceTogether, which uses an open-source protocol called BlueTrace to aid contact tracing using Bluetooth.

In the West, tech giants Apple and Google are teaming up to deploy automated contact tracing to their platforms. Their plan works similarly to the BlueTrace protocol: use Bluetooth to track contacts that have been around you. But how does that work specifically?

The APIs (Application programming interfaces) that Apple and Google are building work more or less like a business card exchange. Your smartphone will have a specific anonymous key. Think of it as a business card, but without any personal information like your name and address, and just a random identification number instead. Whenever your phone gets close to another phone (like when you get close to someone else), they will exchange this information over Bluetooth and storing it for future reference. This exchange won’t be instant — it depends on factors determinant to the spread of the disease, such as physical distance and duration of the interaction.

If one of the people you’ve interacted with within the last 14 days has been diagnosed with COVID-19 and their phone has exchanged keys with yours, you can be notified that you have been exposed to someone that tested positive (of course, without any exposing data, like their name). In case you were the person that has tested positive, you will have the option of notifying those you have interacted with. If you choose to do that, then your phone will upload all the keys it gathered for the past 14 days to the cloud and notify each individual.

Of course, this whole system relies on user consent and adoption. It won’t be enabled by default, but it will require the user to opt-in. This will mitigate privacy concerns, as the process will only take place if the user allows it, but can also hinder widespread adoption.

The companies say that this feature will be rolled out in two phases. The first one, predicted to be released in mid-May, consists of providing contact tracing APIs to public health authorities and organizations that will integrate them into their apps. This phase, while useful at first, might not be widely used, as it requires users to install the apps made by public health organizations.

The second phase of the rollout is where most people will be reached. Apple and Google intend to build contact tracing into their operating systems, iOS and Android, without the need for users to install any apps. This will make digital contact tracing readily available for over 80% of Android devices and over three-quarters of iOS devices. In this case, upon detection of a positive match, the OS will still prompt the user to download the app from their local public health organization for the next steps.

This technology will be crucial in the next steps of the fight against the novel Coronavirus, as governments around the world look for solutions that can help lift stringent lockdowns. Tech companies are giving institutions the tools to help but, for this to work, governments have to step up to the plate. They are the ones who have to adopt this feature into their apps, manage the databases that will keep them running and make the population aware of the importance of opting in. Doing a good job with this will be key to efficiently handle the crisis as social distancing measures are eased across the world.