Test, Test and Test: Understanding COVID-19?

The world is saying “test, test, test”. So why should we test? Well, apart from finding out those that may need help, we also need to understand how much of the population is infected at any time, and use this to understand the spread (and decay) of the virus. Without this we are basically seeing a lag of many weeks (or months), and where it will be too late to understand how the virus is spreading. Without…