Herd immunity may only need 10-20 per cent of people to be infected
From our UK edition
Since mid-March there has been an assumption that herd immunity against Covid-19 would not be achieved until around 60 per cent of the population has been infected. It is a figure which gave rise to the now-famous paper by Professor Neil Ferguson of Imperial College, which claimed that a herd immunity policy (which the government denies ever following) would result in the deaths of 250,000 people in Britain. That figure has been challenged by scientists who have questioned some of the assumptions behind it – for example, it assumed a mortality rate of 0.9 per cent which Imperial College itself has since revised downwards to 0.66 per cent, and some believe is lower still. But today comes another challenge.