Credit Imperial College London
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In addition to its world class genomic sequencing of COVID 19, the UK has been conducting massive randomized antibody and PCR testing of the public - using at-home antibody tests and/or swabs - which are collected from more than 100,000 people for each testing period.
We've looked at results from past REACT antibody studies (see here, and here).
Today we've the result of the first broad assessment of the community's infection rate (by PCR) since the new, more transmissible, B.1.1.7 variant became dominant. Swabs were collected 3 to 4 weeks into the UK's heightened lockdown, although there was little evidence of its impact in this round of testing.
The previous round of testing was conducted between Nov 25th and Dec 3rd, while today's results - recorded between Jan 6th - Jan 15th - indicate a 50% increase in infections, and the highest percentage of community infection detected to date.
We've excerpts from a UK Govt. press release, and a link and excerpts from the report.
January 2021 findings from COVID-19 study published
Initial findings from Imperial College London and Ipsos MORI show infections increased by 50% from early December, with 1 in 63 people infected.
- Over 142,900 volunteers were tested in England from 6 to 15 January 2021 as part of one of the most significant COVID-19 studies.
- It remains paramount everyone stays at home and follows the rules to protect the NHS and save lives.
The interim findings from the eighth report of REACT, one of the country’s largest studies into COVID-19 infections in England, have been published today by Imperial College London and Ipsos MORI.
Over 142,900 volunteers were tested in England from 6 to 15 January to examine the levels of infection in the general population. The findings show infections in England have plateaued at the highest level recorded by a REACT study, with suggestions of a potential uptick. The report does not yet reflect the impact of national lockdown.
Prevalence from 6 to 15 January was highest in London, with 1 in 36 people infected – more than double compared to the previous REACT report in early December. Infections had also more than doubled in the South East, East of England and West Midlands compared to the previous REACT report in early December.
The main findings from the eighth REACT study show:While prevalence has decreased in Yorkshire and the Humber and has remained stable across the East Midlands and North East, infection numbers remain high in all of these regions.
- national prevalence increased by 50% from 0.91% in early December to 1.58%, or 158 per 10,000 infected
- national R was estimated at 1.04
- regional prevalence was highest in London where it had more than doubled from 1.21% to 2.8%. It had also more than doubled in the South East (0.75% to 1.68%); East of England (0.59% to 1.74%); and West Midlands (0.71% to 1.76%). It increased in the South West (0.53% to 0.94%) and North West (0.92% to 1.41%). There was a decrease in Yorkshire and The Humber (1.39% to 0.84%). It was stable in the East Midlands (1.04% to 1.16%) and North East (1.26% to 1.18%)
- prevalence increased nationally in all adult age groups and was highest in 18 to 24 year olds at 2.51%. Prevalence in the over 65s more than doubled from 0.41% to 0.94%
- large household size, living in a deprived neighbourhood, and areas with higher numbers of black and Asian ethnicity individuals were associated with increased prevalence; healthcare and care home workers, and other key workers, were more likely to test positive compared to other workers
- the report contains mobility data for the first time showing peoples’ movement decreased at the end of December and increased at the start of January and helps explain change in prevalence
The figures demonstrate everyone must stay at home to reduce infections, protect the NHS and save lives.
REACT-1: real-time assessment of community transmission of coronavirus (COVID-19) in January 2021
Methodology
Published 21 January 2021
A representative cross-section of volunteers tested themselves with swabs from 6 January to 15 January, inclusive (a small number of tests included were obtained from 30 December and after 6 January). Swabs were analysed using polymerase chain reaction (PCR).
Results
Swab results reported for the period 25 November to 3 December are referred to as round 7b. Swab results reported for the period 6 January to 15 January are referred to as round 8a.
Over the 10 days of the completed round of testing, out of 142,909 swab results, 1,962 were positive, giving a weighted prevalence of 1.58% (95% CI, 1.49%, 1.68%) or 158 people per 10,000 infected. This is the highest prevalence recorded by REACT-1 since it started in May 2020 and represents a greater than 50% increase from 0.91% in round 7b (25 November to 3 December). Within round 8a, the estimated R was at 1.04 (95% CI, 0.94, 1.15). Based on data from a limited number of days, prevalence may have started to rise at the end of round 8a (6 January to 15 January).
Despite a substantial gap between rounds 7b and 8a, changes in prevalence according to region, age and other characteristics may indicate key drivers of the epidemic.
Between rounds 7b (25 November to 3 December) and 8a (6 January to 15 January), there were changes in national prevalence at regional level. Regional prevalence was highest in London where weighted prevalence more than doubled from 1.21% to 2.80%. Prevalence also increased in South East from 0.75% to 1.68%, South West from 0.53% to 0.94%, East of England from 0.59% to 1.74%, and West Midlands from 0.71% to 1.76%. There was an apparent decrease in prevalence in Yorkshire and The Humber, and prevalence was broadly similar (comparing rounds 7b and 8a) in East Midlands and North East.
Patterns of national weighted prevalence by age group showed that between round 7b (25 November to 3 December) and round 8a (6 January to 15 January), prevalence increased in all adult age groups. Prevalence in round 8a was highest in 18 to 24 year olds with a weighted prevalence of 2.51%. Prevalence in those aged 65 and over more than doubled from 0.41% in round 7b to 0.94% in round 8a.
Despite some uncertainty, age-prevalence patterns varied substantially by region. There were large increases from round 7b to round 8a at older ages in London, South East, and East of England..In round 8a (6 January to 15 January) London had the highest weighted prevalence nationally at greater than 2% in those aged 55 to 64 and in those 65 years and over. Patterns in Yorkshire and The Humber, North East and East Midlands did not show increases between rounds 7b and 8a in older adult ages. Prevalence was over 4% in London in those aged 18 to 24 years in round 8a.
Large household size, living in a deprived neighbourhood, and Black and Asian ethnicity were all associated with increased prevalence. There was an increase in prevalence from the smallest to the largest households rising from 1.20% in single person households to 3.46% in households of seven or more people. People living in neighbourhoods in the two most deprived quintiles had prevalence of 1.88% and 1.92% compared with 1.26% for those in the least deprived. Participants of Black and Asian ethnicity had increased prevalence at 3.42% and 2.61% respectively compared with 1.45% among white participants.
Both healthcare and care home workers, and other key workers, had increased odds of swab-positivity compared to other workers in round 8 at 1.66 (1.38, 2.00) and 1.35 (1.20, 1.53) respectively.
Conclusion
During the period 6 January to 15 January, SARS-CoV-2 virus was circulating with a higher prevalence than between 25 November to 3 December with 158 in 10,000 infected. There was no strong evidence for either growth or decay in prevalence averaged across the period 6 January to 15 January.
Subsequent rounds of REACT-1 will allow further accurate assessment of trends in prevalence and transmission.
While there are other regions of the world dealing with various COVID variants, the UK is currently the best equipped country to monitor a more transmissible virus more or less in real time. Not only is COVID B.1.1.7 dominant there, they have the lab capacity to test large swaths of the community on a regular basis.
Given the 50% increase in cases in just over a month, there is little wonder why other nations are viewing the more transmissible B.1.1.7 variant with such concern.
