Lawyer Martin Steiger corrects a dangerous and widespread error on his blog. It is not true that proximity tracking with an app can only serve its purpose if the app is used by 60 percent of the population.
This 60 percent is needed to make the virus disappear. This figure is based on a report by Oxford University in April 2020.
But even if fewer people use such an app, app-based proximity tracking can already reduce the spread. That makes sense, too.
The error becomes dangerous when the 60% obviously cannot be reached and then fewer and fewer people re-install due App and others may even deactivate it.
Therefore: Download and activate the app. Every smartphone counts.