Stuart Neil’s day job keeps him pretty occupied. He’s a virologist at King’s College London, investigating how the coronavirus causing Covid-19 attacks the human immune system. Then, in his own words, he found himself “falling down the rabbit hole” otherwise known as Twitter . Or more specifically, the Twitter debate over how the Covid-19 virus originated, though “debate” could be a kind description for the arguments and accusations that fly over whether the virus jumped naturally from animals to humans or escaped from a laboratory researching coronaviruses in the Chinese city of Wuhan. The duelling narratives have brought internet sleuths,...