Health Traffic Lights contact tracing app wins Hack From Home challenge

Priviacy centric app uses a simple green-amber-red signal to show risk of coronavirus infection

The Hack From Home virtual hackathon, launched two weeks ago in response to the coronavirus crisis, attracted 822 participants from around the globe, with 28 projects submitted.

One of the winning projects was Health Traffic Lights, a contact tracing and symptom tracking smartphone app developed by a team of 15 from around the globe. The project is led by David Flynn, a data analyst from Nashville, USA.

As well as a $10,000 award towards development costs, the team will receive assistance from project organisers Dataswift and the Hub of All Things.

The app works like this. If a user suspects they might have Covid-19, they are encouraged to enter their symptoms into the app. Depending on what they enter, an element in the UI may turn from green to amber and a certain number of points will be added to a risk tally. Anybody coming in close proximity to that person, as detected through GPS, will also have risk points added and could see their app turn amber (although the user's identity is anonymised). They will be prompted to start tracking their health on daily basis via a questionnaire built into the app. Should the original person test positive for Covid-19, their traffic light will turn red and everyone they came into contact with will have their app updated and be prompted to check themselves for symptoms. Conversely, if they test negative risk points may be deducted across the network.

Currently, health authorities around the world are looking to various approaches to contact tracing, with some highly intrusive. However, at this stage Health Traffic Lights is more of a personal tracker, aimed at providing people with information about their risk of having being infected so they can seek treatment and avoid putting others at risk, although its use case could be extended.

Despite using GPS data to track location, it follows the principle of privacy by design, said Flynn, with all data kept in control of the user.

Central to this is a decentralised approach, in which all of the user's data is kept encrypted in a personal data store (a HAT) on the Hub of All things. It is up to the user to decide who should be granted access to this data and they can turn permissions off at any time - such as once the pandemic has subsided - which is not the case for most contact tracers in which personal data is stored centrally and could be deanonymised.

The team chose GPS rather than Bluetooth, as used by other privacy-centric tracing apps, primarily because of familiarity and wanting to get a minimum viable product (MVP) out there as quickly as possible. Bluetooth may be considered in the future, Flynn said.

Health Traffic Lights is still at the MVP stage but the team hope to have a consumer-ready app for download in the next few weeks, probably as open-source code.

"I have a passion for data privacy, and it scares me that data is stored in a centralised way. I've been thinking for a long time there needs to be a way that individuals can control their own data and know where it is. So I found the Hub of All Things and Dataswift and managed to find this hackathon, and it was a perfect opportunity to start working on something that I felt passionate about," said Flynn.

Tracing apps face many technical hurdles. For example, Google and Apple whose OSs are installed on the vast majority of smartphones, have rejected some options put forward by governments on the grounds that they violate user privacy. They also reject some apps that are not approved by aren't from recognised institutions such as governments or hospitals.

So, it's early days for Health Traffic Lights, with many hurdles and tests to come, but the decentralised approach is promising for gaining and maintaining trust.

Flynn is hopeful that the Covid-19 crisis will shine a light on the value of personal data which could herald a change in attitude on behalf of consumers.

"Most people don't understand what personal data is or why it's valuable," he said. "I think in the long term, looking past Covid, we'll be creating tools and platforms that maintain data integrity and ensure it's stored only in that individual's HAT. As a simple example, wearables for health data. Instead of Fitbit taking a copy of that data you can store it in your HAT and ultimately your HAT will become more valuable."