Are common colds keeping flu at bay? plainpicture/OJO/Tom Merton

News that winter flu is rampaging through Britain and threatening Christmas is premature. While the northern hemisphere’s winter flu season has just begun, it seems that another virus might have been keeping it largely at bay in Europe.

Flu is infamous for occasional, deadly pandemics, such as swine flu in 2009, or the epidemic that helped end the First World War in 1918. But the epidemics of “ordinary” flu that take place every winter are deadly too, killing up to 650,000 people with respiratory disease a year, and …