
When last spring Covid-19 struck Manaus, an industrial city of two million on the Rio Negro in Brazil’s Amazon, the outbreak supplied an illustration of just how bad the pandemic could get. Appalling scenes of mass graves and hospitals in collapse were beamed around the world.
As infections finally slowed over the summer, it was speculated that the virus might have ultimately burned itself out there because it was running out of people to infect; that Manaus, as perhaps the most densely infected place in the world, had come close to, or even achieved, herd immunity. According to the US Centers for Disease Control and Prevention, it was estimated that 75 per cent of its population had been infected by October.