Where is the needle flickering on your coronavirus-o-meter: horizontally relaxed? Mild concern? End-of-days panic? Last week I was snorting at a Mumsnet user’s list of the essentials she was stockpiling in case of a long period in isolation: “olive oil, hummus, body lotion, Pringles . . .” By the weekend I was eyeing the tinned goods aisle in Sainsbury’s. The World Health Organisation says the window of opportunity to contain the virus is narrowing. Mecca is closed to foreign pilgrims, Venice has pulled the carnival, Iran cancelled Friday prayers. There are 36 cases here at the time of writing. I am reassured by friends’ predictions that this will be another here today, gone tomorrow Sars or swine flu; then I remember they know as