Digital Contact Tracing 101
A primer on what Digital Contact Tracing is and why it could be the key to getting North America back to business as usual.
If you’ve been paying attention to the news, you’ve probably heard about contact tracing. It has emerged as a beacon of hope for those eagerly awaiting the “return to normal” that seems perpetually out of reach these days and with Google and Apple announcing a joint initiative around contact tracing, there was bound to be a flurry of excited press. But what is contact tracing, exactly? And just how excited should we be?
Contact tracing is actually a well-established (and usually not especially relevant to most people’s lives) practice. So while tech giants are giving hope for a solution that could reach 88% of North American smartphone users — a hugely important metric that would be necessary for digital contact tracing to be effective — the concept behind it is not new. Before we talk about the stats for success, it’s important to understand what digital contact tracing even is and why it’s a potential game-changer in the fight against Covid-19.
What is Digital Contact Tracing?
Digital Contact Tracing (DCT) is an offshoot of Contact Tracing, its older, more established cousin. For decades, epidemiologists, scientists, doctors, and health officials of all types have been using it to track and ultimately slow or even stop the spread of infectious diseases.
Contact tracing works like this:
- Step 1 — Identify an individual with a communicable disease.
- Step 2 — Identify the people who have come into contact with the infected individual and assess their risk of infection.
- Step 3 — Test and encourage self-isolation of at risk individuals, trace their contacts, and repeat steps following the risk of spread to its conclusion.
In this way, public health officials can reduce the rate of infection in the population, which helps slow and even stop the spread of a disease outbreak. By providing health officials information that can help them get ahead of an outbreak, contact tracing can act as a prophylactic against further spread. This is crucial when combatting highly contagious diseases like the SARS-CoV-2 virus that causes Covid-19.
Historically, this has been an extremely labour-intensive process. Officials would literally go door-to-door, gathering information and following the threads of transmission manually. While contact tracing is effective, it can be slow, costly, and put front-line workers at higher risk as they gather the necessary information from the population.
DCT follows the same general guidelines listed above (identify an individual with a communicable disease, track down people who have come into contact with that person, test and repeat with the new individual’s contacts), but it has the potential to speed the process exponentially while reducing risk significantly.
There are a few ways DCT can be implemented, but a current leading contender is through the use of secure Bluetooth technology and an open protocol called DP-3T. Without getting too technical, personal mobile devices (primarily smartphones, but also wearables like a Fitbit could be an option) would create randomized “keys” specific to an individual, but that could not be traced back to that individual. That key would be exchanged with the key from another individual when they came in close contact with one another, and in the event one of them contracted the Covid-19 virus, the exchanged keys could then be used to contact anyone who was in close contact using an alert within the application.
There are a number of nuances to DCT, especially as relates to privacy, and those depend largely on the implementation choices made in development, but the general operation of the system would remain the same. Your mobile device creates keys that are exchanged when you’re in close contact with someone, and should you or someone in your traced close contacts become ill (or even show signs of illness), an alert can notify anyone at high risk and give them the ability to self-isolate, get tested, and increase their vigilance when it comes to stopping the spread.
Privacy Considerations for DCT
The biggest concerns so far surround the privacy and security of this kind of program. Rightly so — depending on the choices made in implementing a DCT system, there could be sensitive personal data involved that could be used in all kinds of ways, both good and bad.
But not all implementations require the collection of private information, and in particular the DP3T protocol does not. And there are obviously compelling reasons for exploring and implementing a DCT program if it can help save lives, especially since it can be done in a way that gives citizens control over their own information while still giving public health providers a significant leg-up in containing the spread.
Making the initiative opt-in is the first and most obvious method for protecting personal information. Use of Bluetooth over GPS or location data is another smart way to provide more privacy for users. Limited time windows for storing keys or other data including a data destruction protocol are other key factors in enabling a program that is effective without causing harm. But it can be done. Notably, the American Civil Liberties Union (ACLU) has outlined .
“Use limitation, data destruction, voluntary participation, transparency and ‘no mission creep’ are the main policies that should be a focal point for the adaptation of any widespread contact tracing protocol. [T]here are several TACT [contact tracing] proposals that aim to be privacy-friendly including DP-3T, PACT, TCN, and the Apple and Google proposal.” — ACLU Statement on Contact Tracing
Beyond Basic Implementation
The ways the data is leveraged and which governing bodies and public health providers have access to it are further complicating factors. At its most basic, a DCT initiative would rely on self-reporting and self-issuing of alerts. But it becomes significantly more effective when appropriate health authorities are notified of areas where an outbreak may be occurring and can then enact measures to slow it.
Pinpointing outbreak hotspots could help cities re-open in a safe manner, enacting temporary closures where risk is high while allowing lower-risk areas to remain operational. The information could allow offices to re-open more safely as well, assuring all that an employee’s risk levels are low and the likelihood of infecting an office are low as well.
DCT is not a silver bullet to ending a pandemic. But it can offer a significant boost to the efforts. Knowledge is power, and the more we can ascertain about where, how, and to whom Covid-19 is spreading, the safer we can all be.
Interested in supporting an open-source digital contact tracing effort? Visit https://www.gofundme.com/f/better-contact-tracing to donate today.