In England, the proportion of people infected by the coronavirus who later died was certainly lower in early August than it was in late June. Over the period, this infection fatality rate (IFR) dropped by between 55 and 80 per cent, depending on which data set was used, found Jason Oke at the University of Oxford and his colleagues.
“This doesn’t seem to be the same disease or as lethal as it was earlier on when we saw huge numbers of people dying,” he says. For example, the week beginning 17 August saw 95 people die and just over 7000 cases across the UK. In the first week of April, 7164 died and nearly 40,000 tested positive.
Dividing deaths by cases gives a crude case fatality rate of around 1 per cent in August, compared with nearly 18 per cent in April.
According to data for England, a larger proportion of younger people are being infected than was happening around the first peak of cases in April, with cases rates for 10-16 August the highest among 15-44 year olds.
Covid-19 is known to be less risky the younger you are, so the changing demographic of those being infected could be one plausible reason that the disease currently seems less deadly.
Several researchers have told New Scientist that the other main possible explanation is that cases are being treated more effectively in hospitals.