Evidence mounts: a new coronavirus variant is more transmissible

VIRUSES reproduce abundantly, and with imperfect fidelity, so mutations are commonplace among them. Most such mutations, though, have little or no effect on how a virus spreads or how deadly it is. And, until recently, SARS-CoV-2, the covid-19 virus, has been no exception to that rule.Regrettably, this seems to be changing. A new variant of the virus, known as B.1.1.7, is spreading rapidly through Britain, and local scientists estimate that it is about 50% more transmissible than other variants currently in circulation. The British authorities are therefore rushing into action to try to limit its spread. Those parts of the country where B.1.1.7 is most prevalent, including London, went into lockdown on December 20th. But cases have been turning up elsewhere, and more areas will be locked down from December 26th. More than 50 countries, moreover, have closed their borders to arrivals from Britain. Some parts of Europe are admitting only those who can show evidence of a recent negative test.