Did Covid cases plateau in March?

Should we be concerned about the latest React study, which claims that the fall-off in new infections began to plateau from the middle of March? The latest instalment of the monthly study, led by Imperial College, tested a randomised sample of 140,000 volunteers between 11 and 30 March, each of whom was given a PCR test. While the results showed that incidence of infections had fallen by 60 per cent compared with tests conducted between 4 and 23 February, the researchers say that their data shows a flattening-off from mid March.

That is interesting because data from the Public health England test and trace system shows a similar pattern: steep falls in new infections during February, followed by a flattening-off in March. For a few days the seven-day average was going in the wrong direction, leading to fears that Britain could be following other European countries towards a third wave. In the case of the PHE figures, however, there was complicating factor – there was a massive increase in testing from 8 March onwards, as schools returned and pupils and teachers alike were asked to test themselves twice a week for the virus.