It is becoming increasingly clear that people are less likely to die if they get covid-19 now compared with earlier in the pandemic, at least in Europe, but the reasons why are still shrouded in uncertainty.
One UK doctor has said that the coronavirus was “getting a little bit less angry”, while an infectious disease consultant at the National University of Singapore claimed that a mutated version of the coronavirus, D614G, is making the illness less deadly.
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. These figures don’t represent the true IFRs at these times, both because deaths lag behind infections by a few weeks,…