Why most Covid-19 deaths won’t be from the virus

It all began with a large hollow tree.

Two-year-old Emile Ouamouno had been fond of playing inside the tree, which was near his home in Meliandou – a village in the heart of the Guinean jungle. But other life had also discovered its cosy confines: bats. Children would sometimes catch them there, before roasting them for dinner.

Then Emile got sick. On the 28 December 2013, he succumbed to a violent and mysterious illness. His mother, sister and grandmother were next. And that was it – after the funeral, the...