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While daily COVID cases reported in the UK are significantly off their Omicron induced peaks of 60 days ago, they remain high, and are showing some signs of increasing (see chart above) as the BA.2 variant increases its dominance in the region.
Directly comparing the HSA's daily COVID case numbers to those reported a month or more ago is difficult since the UK has greatly reduced their testing recommendations in recent weeks, as they attempt to `Live with COVID'.
Less impacted by these policy changes, the UKHSA - in conjunction with the Imperial College London and Ipsos MORI - continue to conduct a monthly broad assessment of the community's infection rate (by PCR) - dubbed the REACT-1 Study - testing a representative cross-section of volunteers in England.
In January, the REACT-1 (round 17) study found the highest prevalence of COVID of the pandemic, wirh ". . . 4,011 samples tested positive from a total of 100,607 valid swab results, giving a weighted prevalence of 4.41% (4.25%, 4.56%) or 441 people per 10,000 infected."
The January Report also noted: The highest rates were observed regionally in the North East and nationally in those aged 5 to 11 years. Of all the positive samples sequenced in this round, 99% of those were Omicron variant; all other lineages were the Delta variant or a sub-lineage of Delta.
Today we've the latest REACT-1 Report (Round 18), which covers the month of February, when BA.2 began to replace the original Omicron variant. While COVID's incidence was down more than 35% over that reported in January, it remains high, and the February REACT-1 study returned the second highest result of the pandemic.
Over the 22 days of testing which form these round 18 findings of REACT-1, 2,731 samples tested positive from a total of 94,950 valid swab results, giving a weighted prevalence of 2.88% (2.76%, 3.00%) or 288 people per 10,000 infected. This compares to a weighted prevalence in the previous round, round 17 (5 January to 20 January), of 4.41% (4.25%, 4.56%), and is the second highest prevalence recorded in a round of REACT- 1.
While the UK saw fewer infections in February, there are also hints of an upward trend in the > 55 age group, which has raised some concerns (see summary below).
All of this matters because the BA.2 variant appears poised to overtake the BA.1 variant globally in the months ahead, and data on how it compares with its predecessors is limited. England is one of the countries where BA.2 got an early foothold, and so we watch its progress carefully.
Thue UKHSA has released the following summary.
Findings from the latest report of the government-backed REACT-1, one of the largest studies into coronavirus (COVID-19) infections in England, have been published today.
From:UK Health Security Agency Published 10 March 2022
Over 94,000 volunteers in England took part in the study to examine the levels of COVID-19 in the general population between 8 February and 1 March.
The latest findings from Imperial College London and Ipsos MORI, covering 8 February to 1 March 2022 (round 18 of the study), show that prevalence in England during this period was 2.88%, significantly down on the 4.41% reported in round 17 (covering January 5 to January 20 2022), but the second highest recorded rate of prevalence rate since the study began in 2020. This means that during the period in which swabs were collected, approximately 1 in 35 people in England were infected with the virus.
Rates of Omicron sub-lineage BA.2 were highest in London, standing at 44.3% of all positive cases in the region. Proportions of BA.2 were also found to be higher in the southern regions compared with the Midlands and northern areas of the country.
While prevalence rates have fallen in all age groups in round 18 from round 17, trends suggest a level or increasing prevalence among those aged 55 and over within this latest round.
Dr Jenny Harries, Chief Executive of the UK Health Security Agency (UKHSA), said:
This data confirms that cases have declined substantially following the peak of the Omicron wave.
However, the increasing presence of the BA.2 sub-lineage of Omicron and the recent slight increase in infections in those over 55 shows that the pandemic is not over and that we can expect to see COVID-19 circulating at high levels.
Vaccination remains the best way to protect us all from severe disease and hospitalisation due to COVID-19 infection. We urge you to come forward for your primary or booster doses straight away if you have not already done so.
Health and Social Care Secretary Sajid Javid said:
It is reassuring to see that COVID-19 cases have continued to fall as we learn to live with the virus and regain our freedoms.
We must continue to protect each other where necessary. Vaccines remain our best line of defence against the virus. If you haven’t already, please Get Boosted Now.
Professor Paul Elliott, director of the REACT programme from Imperial’s School of Public Health, said:
It’s encouraging that infections have been falling across England, but they are still very high and the possibility that they are rising in older adults may be cause for concern.
The good news is that this is a highly vaccinated group. However, a high number of infections will lead to more people becoming ill, so it’s important that people continue to follow public health guidance to avoid fuelling further spread of the virus.
Kelly Beaver, CEO at Ipsos MORI, said:
It is very positive to see prevalence falling month on month, but vigilance remains critical particularly with the concern that we may be seeing a small uptick in cases among the elderly.
REACT has been a vital epidemiological tool over the last 2 years and we would like to thank the over 3 million people who have taken part across the various studies, for contributing to this incredibly important research.
The main findings from the report are as follows:
There were 2,731 positives from 94,950 swabs in round 18, giving an overall weighted prevalence of 2.88%. This is a significant decline in weighted prevalence from round 17, where the figure stood at 4.41%.
A total 1,195 viral lineages were determined from positive samples up to 21 February, all but one of which were the Omicron variant. Of these lineages, 32.7% corresponded to BA.1, 39.6% to BA.1.1 and 27.7% to BA.2.
There was an estimated daily growth rate advantage for BA.2, compared with the 2 other sub-lineages of Omicron with an additive advantage in R of 0.40. The proportion of BA.2 nationwide was estimated at 47.2% as of 21 February 2022.
The highest proportion of BA.2 in this round was observed in London, standing at 44.3%. The next highest proportion of BA.2 prevalence was found in the South West and, in general, BA.2 prevalence was higher in the southern regions compared to the Midlands and northern regions in round 18.
Weighted prevalence was highest in those aged 5 to 11, standing at 4.69%, and lowest in those aged over 75, standing at 1.68%. While prevalence fell in all ages from the previous round, trends suggest a level or increasing in-round weighted prevalence in those aged 55 and above.
Weighted prevalence fell in all regions between round 17 and 18, except in the South East and South West. Weighted prevalence in the South East rose slightly to 3.33% from 3.23%, and in the South West to 3.12% from 2.92%.
At a lower-tier local authority level, of the 10 highest smoothed estimates of prevalence based on a nearest neighbour method, 6 were in London and 4 were in the South West of the country. The local authorities in question were Lambeth, Croydon, Sutton, Merton, Camden, Wandsworth, Bath and North East Somerset, City of Bristol, South Gloucestershire and North Somerset.
The limited evidence we've seen to date indicates the BA.2 variant is more transmissible than BA.1, but it doesn't appear to produce more severe illness or worse outcomes. That said, Omicron continues to evolve, and past performance is never a guarantee future results.
As tempting as it is to declare the pandemic over, the virus is just getting started in some parts of the world, and it may yet have some surprises left.
