React

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

It seems that Boris Johnson will not begin to think about lifting lockdown restrictions until we have clear evidence that the latest wave of the virus has almost been defeated. So it was not exactly good news yesterday from Imperial College’s React Covid survey, which suggested that even though we are in lockdown, the R number is still almost at 1 in Britain – meaning the epidemic is barely shrinking. As part of React’s ‘viral opinion poll’ swabs were taken from over 160,000 people in England between 6 and 22 January. And while the researchers rowed back on a claim in their previous report that active infections could be rising

Yesterday, the news was dominated by Imperial College’s React study which suggested – in contrast to the fall in recorded new infections – that the prevalence of Covid-19 in the general population was either static during the first ten days of lockdown (between 6 and 15 January), or could even have risen slightly. This morning, however, we have a second opinion in the form of the ONS infection survey, which like React is based on testing a randomised sample of the population. It suggests that the prevalence of Covid-19 did indeed fall in the first half of January – but not by all that much. Between 9 and 16 January,