Coronavirus reinfection cases: What we know so far and vital missing clues

Vaccines work by creating memory cells without the risk of a potentially fatal infection. In an ideal world, it would be relatively easy to create immunity, but it's not always that straightforward

As President Trump claims that he is immune to COVID-19 and isolated reports emerge of reinfection, what is the truth about immunity to COVID-19?

To date, there have been six published cases of COVID-19 reinfection, with various other unverified accounts from around the world. Although this is a comparably small fraction of the millions of people known to have been infected, should we be concerned? To unpick this puzzle, we must first consider what we mean by immunity.

How immunity works

When we