LONDON: British public health officials were baffled. Restrictions across the country reduced the spread of coronavirus to much of the country in late November. But in a part of the south-east of England the infections increased inexplicably.
Epidemiologists set out to investigate, initially assuming that there had been some sort of super-spreader event or that people were ignoring the rules of social distancing at work, at illegal parties at home, or elsewhere. They found nothing. Shaken, they turned to a team of scientists who were monitoring mutations in the virus’s genome.
On December 8, the group, known as the Covid-19 Genomics UK Consortium, found a new variant of the virus, with 23 mutations, in a sample taken from a patient in Kent, near the center of the outbreak in late September. They found the same variant in someone tested in London a day later.
Some of the new mutations could increase the transmissibility of the virus.
“Gathering genome data and details of an outbreak in Kent led to the key connection,” said Sharon Peacock, the University of Cambridge microbiologist who heads the genomics team. He said in an email that it was scientists’ “light bulb moment.”
Out of control
The UK stepped up restrictions after announcing a new variant of the coronavirus that appears to be more transmissible.
The two-week percentage change in the new confirmed daily cases of Covid-19
Note: change in Luxembourg calculated from data for 10 December; Spain from 9 December.
Source: Johns Hopkins CSSE
New information continued to flow and the British government first raised concerns about the variant on December 14, when Health Secretary Matt Hancock told British lawmakers he had been responsible for 1,000 cases in London and in the south-east of England and which was spreading.
“Initial analysis suggests that this variant is growing faster than existing ones,” Hancock said.
Meanwhile, scientists delved into the nature of the mutations in the new variants.
Viruses mutate all the time, although coronaviruses are slower than some other common viruses like the flu. What stood out in the new variant was that a larger number of the usual mutations affected the code of amino acids produced by the proteins that make up the virus.
A mutation alters the virus’s ear protein in a way that is known to make it easier for the virus to stick to cell walls and enter the body. Along with two other mutations, the change may give the variant a possible advantage over previous versions in infecting people.
It was a variant that had not been seen until now, and the number and nature of its mutations, according to scientists, was unprecedented.
“It’s kind of a branch, it’s really quite amazing that it’s so different from the rest of the UK,” Drs. Peacock.
At the time of the discovery of the new variant, it accounted for 62% of all cases registered in London. And infections have continued to rise rapidly.
The latest data show that the average of seven days a week from Wednesday to Wednesday across the UK rose 61% from the previous week, although the number of cases fell in most of the rest of Europe. . Hospitalizations and deaths, delayed indicators of virus spread, increased by 16% and 20%, respectively.
“The underlying mechanism” that drives rapid spread “is not entirely clear, it could be because the virus reproduces faster, which means you get higher viral loads, which means you’re more infectious,” said Peter Horby , president of new emerging respiratory virus threats. The advisory group was advising the British government, lawmakers said Wednesday.
Tuesday public health messages outside Victoria Station in London.
Photo:
Wiktor Szymanowicz / Zuma Press
Another hypothesis is that a shorter time may elapse between being exposed and being infectious, which would lead to faster transmission. “Or it may mean that the duration of the infection is longer,” Dr. Horby.
Researchers are now working to answer two crucial questions: Will the new variant cause more serious illnesses and be able to evade vaccines?
British scientists say they don’t have enough evidence right now to answer definitively, but that they are working hard to find out.
In the vaccine, they are testing blood samples from people who have had the vaccine against the new variant to see if they show a different response compared to the one they got the previous version.
The images show empty supermarket shelves as cargo trucks run aground at the border after France imposed a ban on travel to Britain following the spread of a new coronavirus strain. Other countries have also banned UK passengers Photo: Neil Hall / EPA / Shutterstock
The widespread view among Pfizer scientists and developers Inc.
– The BioNTech SE vaccine is that the vaccine produces antibodies that attack various sites of the virus, so changes in a small area are unlikely to neutralize the potency of the vaccine.
On the severity of the disease caused by the new variant, they are waiting for hospitalization and mortality data, which are cases of delay, to explain them further.
As they delved deeper into the new variant, British researchers have spent the last few weeks quietly searching for the zero patient. They analyzed the contacts of the two people who were the first to be identified with the variant, neither of whom was ill, and others who became infected earlier.
One hypothesis is that the variant arose in a person with a compromised immune system. People with deficient immune systems are usually the host when viruses undergo a large number of mutations because the virus can survive in their system for so long.
“In an ideal situation, you would know who the index case was,” Dr. Peacock said. “We don’t know at all, whether this has arisen in a patient in the UK or whether it has been introduced, at the moment we categorically cannot know.”
The week after the new variant was made public, new data and epidemiological modeling made British scientists increasingly convinced that the new variant was reproducing faster than its predecessors. Some models suggested that it was 50% to 70% more transmissible than other versions.
On December 18, as new infections in the region continued to accelerate, a meeting between government officials and scientists alarmed the government, prompting a significant change in policy.
The next day, Prime Minister Boris Johnson announced new blockades for regions where the virus was spreading rapidly and reduced the relaxation of the five-day Christmas restrictions planned to a single day in the rest of the country.
Write to Joanna Sugden to [email protected] and Stephen Fidler to [email protected]
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