Pandemic theatre

Canada is the latest country to announce that they are rolling out a contact tracing app for covid-19. There are so many issues with this idea, and its timing, that we have to consider it as pandemic theatre.

These contact tracing apps work as follows: each phone is given a random identifier. Whenever your phone and somebody else’s phone get close enough, they exchange these identifiers. If anyone is diagnosed with Covid, their identifier is flagged and all of the phones that have been close to the flagged phone in the past 2 weeks are notified so that users know that they have been close to someone who subsequently got the disease.

First, Canada is very late to the party. This style of contact tracing app was first designed by Singapore, Australia rolled its version out at the end of April, and many other countries have also had one available for a while. Rather than using one of the existing apps (which require very little centralised and so specialised infrastructure), Canada is developing its own — sometime soon, maybe.

Second, these apps have serious drawbacks, and might not be effective, even in principle. Bluetooth, which is used to detect a nearby phone, is a wireless system and so detects any other phone within a few metres. But it can’t tell that the other phone is behind a wall, or behind a screen, or even in a car driving by with the windows closed. So it’s going to detect many ‘contacts’ that can’t possibly have spread covid, especially in cities. Are people really going to isolate based on such a notification?

Third, these apps, collectively, have to capture a large number of contacts to actually help with the public health issue. It’s been estimated that around 80% of users need to download and use the app to get reasonable effectiveness. Take up in practice has been much, much less than this, often around 20%. Although these apps have been in use for, let’s say, 45 days in countries that have them, I cannot find a single report of an exposure notification anywhere.

Governments are inclined to say things like “Well, contact tracing apps aren’t doing anything useful now, but in the later stages they’ll be incredibly useful” (and so, presumably, we don’t have to rush to build them). But it’s mostly about being seen to do something rather than actually doing something helpful.