Unprecedented levels of coronavirus infection have been recorded in England this month and Omicron has almost completely replaced Delta, data suggests.
The highest prevalence was seen in primary schoolchildren at 7.81 per cent, while overall it was 4.41 per cent between January 5-20 this year.
This means that during this period, one in 23 people in England was infected with Covid-19 in January.
This is the highest figure since the beginning of Imperial College London’s React-1 study, which has been running since May 2020.
It is also more than three times higher than the prevalence in the previous round of the study, which focused on data from November 23 to December 14.
Overall, the data suggests the peak of the wave was around January 5, with cases flattening by the middle of the month.
The data also indicates that, while prevalence was decreasing among adults in January, it was rising in children.
Meanwhile, of the 3,582 people who reported whether or not they had previously had Covid-19, two thirds (64.6 per cent) reported a past infection.
Researchers urged caution, however, saying it is unknown when those past infections were and that PCR tests can return positive results for more than 90 days after diagnosis.
The increase in prevalence corresponds to Omicron becoming the dominant variant in England, the researchers added.
Over the study period, prevalence increased in every region compared to the previous report, with the highest figures recorded in the North East at 6.85 per cent, followed by Yorkshire and the Humber at 5.58 per cent.
“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 React programme at Imperial’s School of Public Health.
“Of particular concern is that there is rapidly increasing prevalence among children now they are mixing more following the start of the school term and, compared with December, prevalence in older people aged 65-plus has increased seven- to 12-fold, which may lead to increased hospitalisations.
“It’s therefore vital that we continue to monitor the situation closely to understand the impact of the Omicron variant, which now makes up almost all infections in the country.”
“It’s reassuring to see Covid-19 infections beginning to slow across the country as we move back to Plan A,” said Health Secretary Sajid Javid.
“Covid-19 rates are still high so, as we learn to live with the virus, it is vital we continue to be vigilant — wash your hands, let in fresh air, get tested and, if you haven’t already, get boosted now.”