Last Tuesday an email landed in Neil Ferguson’s inbox from his boss, Alice Gast, the president at Imperial College London. She had two things to say to Prof Ferguson, an influential epidemiologist whose work had just been credited with helping to upend coronavirus response strategies on each side of the Atlantic: thank you for everything you’re doing and try to get some rest.

His initial response was typical, Prof Gast said. “He asked me to write again to his whole team with a message he could forward?.?.?.?He’s a very collegial academic.” Then he said something startling. “He told me he had a dry cough.”

That was a classic coronavirus symptom. So was the high fever Prof Ferguson soon developed. By Wednesday morning he was tweeting that he felt “a bit grotty” as he hunkered down for seven days of isolation in his central London flat. A test confirmed he had been infected by the virus he was modelling.