‘What’s in a name? That which we call a rose by any other name would smell as sweet,’ wrote the Bard. He was referring to a rose which is a rose, instantly recognised by its fragrance and its appearance. But a case of Covid-19 does not fit the metaphor, because it differs wherever you look.
In the course of our evidence gathering activities, we have gone through a few thousand papers reporting studies on all aspects of Covid-19 spread. We found that not very many defined a case of Covid, which is a sign of sloppiness when that is what you are looking for. Those that did, reported different definitions and ways of ascertaining what they meant by a ‘case’.