LONDON (Reuters) - An English COVID-19 study reported record prevalence in January after an Omicron-fuelled spike in infections, Imperial College London said on Wednesday, adding that infections had dropped back from their peak but were now plateauing.
England will on Thursday ditch mask mandates and COVID-19 vaccine passes introduced to slow the spread of Omicron. Prime Minister Boris Johnson has credited the success of Britain's booster rollout and the lower severity of the variant as he aims to live with COVID-19.
Britain has so far recorded more than 150,000 deaths from COVID-19, and daily infections peaked during the Omicron wave.
Imperial found that prevalence of infections between Jan 5 and Jan 20 was 4.41%, more than three times higher than it was in December.
Although prevalence decreased over the course of the month, the overall trend was unclear by the end of the study period, with cases rising in children and falling in adults.
"There is good news in our data in that infections had been rapidly dropping during January, but they are still extremely high and may have recently stalled at a very high prevalence," said Paul Elliott, director of the Imperial REACT programme.
Omicron had also almost entirely displaced Delta, with only 1% of sequenced swabs belong to the formerly dominant variant.
It found prevalence among over-75s of 2.43%, a lower proportion than in the population overall but still "a high level of infection among a highly vulnerable group," the researchers said.
Nearly 65% of people asked reported that they had a confirmed previous infection. However, Elliott said that while some of these could be reinfections, they could also be the same, recent infections being picked up a second time by the survey.
(Reporting by Alistair Smout; editing by William James)