Reasons why Covid variant could kill more people are uncertain

Whatever the answer, everyone has to try even harder not to catch it in the first place

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Those who may have been comforted in recent weeks by the evolutionary theory of virus mutation - that the more transmissible they become, the less lethal they are - may now be pondering the news that the variant that originated in Kent not only spreads more easily but may kill more people too.

Britain's chief scientific adviser, Sir Patrick Vallance, at the Downing Street press briefing, said it could be that in people over 60 with Covid, 13 or 14 might die in every 1000, instead of 10 as has been the case. The reasons still seem to be uncertain.