This morning, the public health agency in the Northern Italian city of Bergamo – the epicentre of the Italian outbreak in March – reports that a random sample of 9,965 residents from the worst-affected areas show the presence of antibodies in a remarkable 57 per cent of cases.

We knew things were bad in Bergamo, but the numbers are on a different scale to those experienced elsewhere. In New York City, for example, sampling suggested that 21 per cent of the population had caught the virus. No less remarkably, the Bergamo study suggested that the infection rate was higher in the general population than it was among healthcare workers, 30 per cent of whom were found to have antibodies to the virus. Bergamo was put into lockdown on 8 March – one of the earliest places in Italy – so the figures do not speak much for the effectiveness of such measures. Somehow, the virus managed to infect a population which was supposed to be in quarantine. Neither do they appear to support the notion that there is a natural limit of around 20 per cent of people who are susceptible to the virus – a figure which has cropped up again and again in places such as the Diamond Princess cruise ship and in New York.