Amid fears that the border with France will be closed, people are waiting at London’s St Pancras station for the last train to Paris today. Belgium said earlier today that it would ban at least 24-hour trains from London.
A.P. Images by Stefan Russo / P.A.
By Kai Kupferschmidt
ScienceThe report of COVID-19, supported by the Putitzer Center and the Heising-Simmons Foundation, is supported.
On December 8, during a regular Tuesday meeting about the spread of the epidemic coronavirus in the United Kingdom, scientists and public health experts saw a figure from which they sit upright. Nick Loman, a microbial genomist at the University of Birmingham, says there has been a sharp rise in cases in Kent in the south-east of England, and a phylogenetic tree depicting a viral sequence from the county looked very strange. Not only did half the cases occur due to a specific type of SARS-COV-2, but that variant was sitting on a tree branch that literally hung out from the rest of the data. “I don’t see a part of the tree like this,” says Loman.
Less than two weeks later, that conversion causes mayhem in the United Kingdom and elsewhere in Europe. Yesterday, UK Prime Minister Boris Johnson announced tougher lockdown measures, saying tensions, which go by the name B1.1.7, seem better spread among the people. The news caused many Londoners to leave the city today before the new rules came into force, causing congested train stations. Today, the Netherlands, Belgium and Italy announced that they were temporarily suspending passenger flights from the United Kingdom. The Eurostar train between Brussels and the British capital will run for at least 24 hours at midnight tonight.
Scientists, meanwhile, are trying to figure out whether B.1.1.7 is really more adept at human-to-human transmission, not everyone is sure – and if so, why. They are also wondering how it grew so fast. B.1.1. It has achieved 17 changes simultaneously, a feat never seen before. Andrew Rambutt, a nuclear evolutionary biologist at the University of Edinburgh, says, “There is now a strong pressure in the lab to try and characterize some of these changes.”
Too many strangers
Researchers have seen SARS-COV-2 evolve in real time more than any other virus in history. So far, it accumulates changes at a rate of 1 to 2 changes per month. This means that many of the genomes created sequentially today differ by about 20 points from the initial sequence genomes in China in January, but there are also many variants with fewer variations. “Since we monitor the genome very closely, you can see almost every step,” says Loman.
But scientists have never seen a virus achieve more than a dozen mutations at once. They believe it happened during a long infection of a single patient, which allowed SARS-CoV-2 to go through an extended period of rapid development, with many types competing for the benefit.
One reason for concern, Rambaut said, is that there are 17 to eight mutations in the gene that encode spike proteins on the viral surface, two of which are particularly worrisome. One, N501Y, has previously shown how tightly the protein binds to the ACE2 receptor, its entry point into human cells. Another, named – 70 Dale, spike leads to the loss of two amino acids in the protein and has been found in viruses that trigger an immune response in some immunocompromised patients.
The lab is now under a tremendous pressure to try and characterize some of these changes.
Lucky coincidence helped to show that B.1.1..7 (also called VUI-50606/01, for the first “under investigation type” in December 2020), faster than other types in the United Kingdom Appears diffuse. One of the most widely used PCR tests in the country, called Takpath, usually detects fragments of three genes. But the 69-70 deal virus spike gene leads to a negative signal for the encoding gene; Only two genes will be shown instead. This means that PCR tests, which the UK performs by the hundreds of thousands every day and are faster and cheaper than indexing the entire virus, could help keep track of B.1.1.7.
At a press conference on Saturday, Chief Science Adviser Patrick Wallens said B1.1.7, which was isolated from the first virus on September 20, accounted for about 26% of cases in mid-November. “By the week beginning December 9, the numbers were much higher,” he said. “So, in London, there were more than 60% new variables in all cases.” Boris Johnson added that the transmissibility of the virus has increased by 70% due to a number of mutations.
Christian Drosten, a virologist at Berlin’s Charity University Hospital, says it was premature. “There are too many strangers to say something like that,” he says. For one thing, the rapid spread of B1.1..7 may reduce the chances. Scientists previously worried that a species that spread rapidly from Spain to the rest of Europe – confusingly called B1.1. – might be more transmissible, but today they believe it is not; It has just been transported across Europe by travelers spending their holidays in Spain. BJ.1..7. Something similar is happening with Georgetown University virologist Angela Rasmussen. Drostein notes that the new mutant also kills another viral gene, ORF8, which previous studies suggest reduces the virus’s ability to spread.
But more cause for concern comes from South Africa, where scientists have sequentially created genomes in three provinces where cases are on the rise: Eastern Cape, Western Cape and KwaZulu-Natal. They identified a different lineage from the UK variable that also has a N501Y mutation in the spike gene. “We have found that the lineage is spreading faster,” says Tulio de Oliveira, a virologist at the University of KwaZulu-Natal. (A printout of their results on the stress, which they call 501Y.V2, will be released on Monday, Oliveira says.)
Another concern is that B.1.1.7 could cause more serious disease. John Nekengasang, director of the Africa Centers for Disease Control and Prevention, said the South African type could change among young people and those who are otherwise healthy. “It’s relevant, but we really need more data to make sure.” The African Task Force for Coronavirus will convene an emergency meeting on Monday to discuss the issue, Nekengasang said.
However, the stress of B.1.1.7777, Spain, teaches a cautious lesson, says Emma Hodcroft, a virologist at the University of Basel. UK scientists initially thought it had a 50% higher mortality rate, but in the early days it turned out to be “completely inconsistent, biased information”. “I think it’s a very strong reminder that we should always be really careful with the initial data.” In the case of N501Y, more young people may become ill, as many more become infected; Olivira says some recent post-exam celebrations in South Africa have turned into over-enthusiastic events. Studies in cell culture and animal experiments will have to show how a virus with many or all of the mutations made by a new variant compares to previous variants, Drosten says.
Getting accurate answers can take months. But Cambridge University virologist Ravindra Gupta has made a start. Months – 70 Dell change d. months66 appeared simultaneously in the virus with another mutation called H in a patient who had been infected for several months and was given concave plasma to treat the disease. (The patient eventually died.) In the laboratory, Gupta’s group found that the virus carrying both mutations was less susceptible to many donors’ concave plasma than wild-type viruses. Gupta wrote in a preprint published this month that he could avoid antibodies targeting the wildlife virus. He also gave a lentivirus to express modified versions of the spike protein and found that the virus alone became twice as contagious as the caterpillar. It is now doing similar experiments with viruses that lead to both deletion and N501Y mutation. Gupta says the first results should appear only after Christmas.
Does it happen elsewhere?
Hawkcroft says the ban on flights from the United Kingdom or other countries is “extreme”. But it does give countries time to think about taking any additional steps to deal with passengers from the United Kingdom, she says: “I hope most countries in Europe think about this.”
But scientists say that B.1.1. May already be more comprehensive. Dutch researchers have found it in a patient sample taken in early December, writes Dutch Health Minister Hugo de Jones. In a letter to Parliament today. They will try to find out how the patient became infected and if there is a related case. Harvard T.H. William Henag, an epidemiologist at Chan School Public Health, said other countries could have similar variables; The United Kingdom may have just taken it first as it is the country with the most sophisticated SARS-Co-2 genomic monitoring in the world. In many countries the rank is low or none.
The evolutionary process that led to B.1.1.7 may occur elsewhere. Christian Anderson, an infectious disease researcher at Scripps Research, says that as the vaccines are being rolled out, the pressure of choice on the virus will change, which means it helps the virus to develop. Anderson says the important thing in the coming months is choosing such events. “Everything that became possible with the emergence of the B1.7 line lineage is probably going on in other parts of the world,” he says. “Can we really find it and then follow it? That’s an important thing for me.”
