A curious sight greeted London-based clerk Robert of Avesbury in September 1349: a parade of “flagellants” marching through the streets chanting prayers and whipping one another with scourges until blood flowed down their backs. It was a grisly procession, but it had a positive purpose: these adherents of a penitent sect were trying to persuade God to ease the grip of a pandemic that had seized every city in Europe – the first wave of the Black Death. This outbreak of plague, which began in Asia and swept into Europe through the cities of northern Italy, went on to kill between 40 and 60 per cent of the continent’s population.
Today we do not recommend scourging parties as a cure for pandemic disease. (In fact, they would probably be called superspreader events.) Most of us put our faith in science, not God, and in social distancing and vaccination rather than prayer and penance. Yet recent experience has shown that humans are still highly vulnerable to rapidly transmissible illness, just as we were in the Middle Ages.