Coronavirus rates in England are similar to where they were in January of this year, just after the peak of the second wave, new data suggests.
From mid-October to early November 2021, the prevalence was 1.57% – the same as in January – compared to 0.83% in September.
According to the data, the prevalence increased between Round 14 and 15 of the Imperial College London React-1 study in most age groups and regions.
During cycle 15, which ran from October 19 to November 5, there was a decline in the prevalence of a peak around October 20 to 21.
School-aged children had the highest infection rates with a prevalence of 4.95% among those aged 5 to 12 and 5.21% among those aged 13 to 17.
The data suggests that all cases were the Delta variant or sublines. The most prevalent was AY.4, which scientists say is more likely to lead to asymptomatic infection.
Christl Donnelly, professor of statistical epidemiology at Imperial College London, said: “It is absolutely true that if people wait for symptoms to get tested and therefore identify that they are infected, and therefore reduce their contact, being asymptomatic can facilitate transmission, for example.
“It’s the asymptomatic transmission that can really make the difference between what is relatively easily controlled and what requires vaccination.”
The AY.4.2 mutation that authorities are monitoring as a “study variant” accounted for 11.8% of infections.
The researchers say the observational nature of the survey data and the relatively small proportion of unvaccinated adults call into question the comparability of the vaccinated and unvaccinated groups.
However, they found that third doses of the vaccine for eligible adults and immunization of children aged 12 and older are associated with a lower risk of infection.
Researchers say they should therefore remain a high priority – with possible extension to children aged 5 to 12 – and this should help reduce transmission of Covid during the winter.
The study was published as a preprint which has not been peer reviewed and is not published in a journal.