In an effort to assist with the technical contact tracing solutions that health authorities have implemented (or are implementing) around the globe, Apple and Google have announced a two-stage rollout of contact tracing technologies in Android and iOS.

From Apple’s press release:

First, in May, both companies will release APIs that enable interoperability between Android and iOS devices using apps from public health authorities. These official apps will be available for users to download via their respective app stores.

Second, in the coming months, Apple and Google will work to enable a broader Bluetooth-based contact tracing platform by building this functionality into the underlying platforms. This is a more robust solution than an API and would allow more individuals to participate, if they choose to opt in, as well as enable interaction with a broader ecosystem of apps and government health authorities.

Privacy, transparency, and consent are of utmost importance in this effort, and we look forward to building this functionality in consultation with interested stakeholders. We will openly publish information about our work for others to analyze.

The first stage—APIs that enable interoperability between Android and iOS devices  using existing health authority apps—is a welcome one. In Singapore, we use TraceTogether and one of the key limitations is that it can only talk to other devices on the same platform. Enabling cross-platform connectivity will give contract tracing a much-needed boost.

The second stage—building contact tracing functionality into the OS—resolves the adoption problem currently faced by standalone contact tracing apps. For example, TraceTogether has 1,000,000 users which, while a sizeable sum, is only about 17% of the population. Building functionality into the OS will make it available to everyone, which is a good thing. This is echoed by the TraceTogether team, on their blog:

Adoption has always been one of TraceTogether’s weaknesses. We needed high adoption rates for it to be effective. It matters not only that you have it installed; it also matters that everyone around you also has it installed. But this is also TraceTogether’s greatest strength: that it requires all of us coming together, each engaging in a small act of social responsibility, but collectively strengthening our communities, protecting those around us and ourselves. #SGUnited and #SingaporeTogether. When we TraceTogether, we are safer together.

With this announcement, I still have two open questions:

  • While the announcement indicates that the technology is opt-in and privacy focussed—it uses Bluetooth proximity and not GPS location data—there are privacy considerations once COVID-19 subsides. Will the contact tracing technology be removed? Will it be disabled? What’s the exit strategy? These questions need to be answered by Apple and Google.
  • When the OS-level technologies are released there will be a much higher number of users. How will health authorities filter out actual close contact vs. devices passing each other briefly vs. devices nearby but in a different unit (e.g. your neighbours)?

I was concerned about the privacy implications of TraceTogether when it was first released. However, having read about how it works, those concerns were put to rest:

  • This is not a location-tracking solution (GPS is not used)
  • Your mobile number and a random user ID is stored on TraceTogether’s server, but can be removed at any time on request
  • Data about phones that you’ve been near is held on-device and can only be uploaded with your consent
  • You can stop TraceTogether’s functionality by simply removing the app

I am therefore optimistic that the technologies coming from Apple and Google—largely based on TraceTogether—will assist in the global fight against COVID-19.