Passengers wearing masks wait to board trains at the Beijing West Railway Station, in Beijing, China January 20, 2020. | Reuters/Stringer
My old editor at The Observer, David Astor, used to say: “There are some problems in the world to which we think we know the answers. There are other problems to which there are no answers. A third category is problems to which there may be answers, but we don’t happen to know what they are.” Coronavirus (or Covid-19, as we must learn to call it) falls into that third category.