The new SARS-CoV-2 variant is growing fast, is more transferable than other variants and has a larger percentage under 20s.
The new variant has a transfer advantage of 0.4 to 0.7 in reproduction number compared to the previously observed voltage.
The findings are in a pre-print written by a collaborative team from Imperial College London, University of Edinburgh, England Public Health (PHE), the Wellcome Sanger Institute, the University of Birmingham and the COVID-19 Genomics UK (COG). -UK). Consortium +.
New variant of concern
This higher transmissibility will complicate control and further emphasize the urgency of vaccination as soon as possible. Professor Neil Ferguson Imperial College COVID-19 Response Team
All viruses undergo genetic changes called mutations and can result in different variants through selection. The variant of SARS-CoV-2 (the virus that causes COVID-19) was originally named B.1.1.7, was detected in November 2020 and spread rapidly across England. Various genetic changes (substitutions and deletions) have immunological significance and are associated with failures in diagnostic tests. The absence of S target in an otherwise positive PCR test appears to be a very specific marker for the B.1.1.7 pedigree, now recognized by Public Health England as a Variant of Concern (VOC) 202012/01 has been designated.
Using a variety of statistical approaches, the team evaluated the relationship between the transmission and the frequency of the new variant across regions in the UK over time.
Using the appearance of whole genomes of different genetic variants through time and philodynamic modeling (dynamics of epidemiological and evolutionary processes), researchers show that this variant is growing rapidly.
The study finds a high correlation between VOC frequency and something called S-gene target failure (SGTF) in the routine PCR test of community cases. This enabled the researchers to use SGTF frequency as an estimate of VOC and non-VOC incidence per region over time, showing that VOC frequency is associated with epidemic growth in almost all areas.
There is a consensus among all analyzes that the VOC has a significant transfer advantage (increased transfer compared to non-VOS), with the estimated difference in reproduction numbers between VOC and non-VOC between 0.4 and 0.7, and the ratio between reproduction numbers varies between 1.4 and 1.8.
These higher levels of infection occurred despite the high levels of social distance in England. Extrapolation to other transmission contexts requires caution, the researchers say.
Under 20s more affected
The study found that individuals younger than 20 years account for a greater percentage of VOC cases than non-VOC cases. However, according to the researchers, it is too early to determine the mechanism behind this change. They explain that this could be partly influenced by the distribution of the variants that coincided with a period where lock-in was in force but schools were open. Further research is underway on the specific nature of any changes in the influence of the virus on this age group.
Dr Erik Volz of Imperial College London said: ‘All viruses develop and very rarely will a virus change in a way that requires us to evaluate public health policy. We find overwhelming evidence of a change in the transmissibility of the B.1.1.7 variant that must be taken into account when planning our COVID-19 response in the new year. ‘
Prof Neil Ferguson of Imperial College London said: “These analyzes, which have informed the UK Government’s planning in recent weeks, show that the new variant of concern, B.1.1.7, has significantly higher transmissibility than previous SARS-CoV-2 viruses spreading in the UK. has. This will complicate control and further emphasize the urgency of vaccination as soon as possible. ”
Prof Axel Gandy of Imperial College London said:
“Until a very large part of the population is vaccinated, strong social distance measures are needed to control this more transmissible variant of COVID-19. Everyone who can be vaccinated must be vaccinated.”
Dr Meera Chand, incident director for Covid-19 at PHE, said:
“These new analyzes provide further evidence of the increased portability of the new variant of COVID-19.
‘We now have two vaccines that are licensed, but this research highlights the importance of doing everything in our power to reduce the spread of the virus while the vaccines are being rolled out. The basics remain very important: adhere to social distance and stick to the constraints that are there. ”
Jeffrey Barrett of the Wellcome Sanger Institute, said:
‘By combining the UK’s high-throughput genomic surveillance with data from community tests across the UK and advanced statistical models, we have been able to understand how the new variant of the COVID virus is spreading. This is true proof of scientific teamwork that everything came together so quickly. ”
This research was the result of a collaboration between scientists at: (a) the MRC Center for Global Infectious Disease Analysis, J-IDEA, Imperial College London; (b) Department of Mathematics, Imperial College London; (b) Institute for Evolutionary Biology, University of Edinburgh; (c) Public Health England; (d) Wellcome Singer Institute; and (e) School of Biosciences, University of Birmingham.
Since the emergence of the new coronavirus (COVID-19) in December 2019, the Imperial College COVID-19 Response Team has adopted a policy to immediately share research findings on the evolving pandemic.