LONDON – Scientists around the world are competing to assess the dangers posed by a new variant of the coronavirus that has spread rapidly in Britain as more countries close their borders to UK travelers in an effort to prevent it.
Epidemiologists and virologists who advised the British government say initial evidence indicates that the new strain is more contagious than previous variants, but that so far there are no signs of causing more serious illness.
Transmissibility (the ease with which the virus spreads from one person to another) and the severity of the disease it causes are important metrics for measuring potential threat. And scientists say there’s still a lot they don’t know.
Viruses mutate naturally, especially RNA viruses like the new coronavirus. Many variants of the new coronavirus have appeared since it ran around the world.
Worrying mutations
A new strain of coronavirus spreading in the UK has genetic changes that could make it better in cell infection.
Several changes, or mutations, were found in genes encoding the tip proteins on the surface of the virus.
The tip proteins bind to the receptors on the surface of the cells, helping the entry of viruses.
Scientists are still studying the effects of these mutations on how quickly the virus spreads.
Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said he expects the variant to circulate in the United States if it is no longer in the country, but said he did not believe it had been a factor the current increase in infections in the US
He said he did not believe the US needed to stop flights from the UK, but that “I think you might want to consider requiring people who board a plane and fly from England to have tested in the last 48 to 72 hours “.
Dozens of countries around the world have moved to curb travel from the UK. The US has not done that. New York has asked airlines to require all passengers in the UK to take a negative Covid-19 test before boarding flights into the state.
Health experts and pharmaceutical industry officials say they hope the newly licensed vaccines, which induce responses to the virus targeting different areas of the pathogen’s surface, will protect against the new variant.
Ugur Sahin, CEO of BioNTech SE,
which was associated with Pfizer Inc. in a vaccine, he said Tuesday he thought the shot would work against the new version of the virus, but that if it is more transmissible, it could raise the threshold needed to protect the community.
“If the virus becomes more efficient in infecting people, we may need even a higher vaccination rate to ensure that normal life can continue uninterrupted,” he said.
France, Israel and Canada are some of the countries that have banned travelers from Britain in an effort to prevent a new highly infectious strain of the coronavirus that is spreading rapidly in England. Photo: Getty Images
Still, David Dowdy, an epidemiologist at the Johns Hopkins School of Public Health, said higher vaccination rates would not be necessary, even if the variant proves more transmissible, as long as enough people are inoculated.
“If we are able to successfully vaccinate a large part of the population, I don’t think the additional transmissibility of this variant is enough to overcome that strong effect,” he said.
The UK government was alerted in recent days to data suggesting the new variant was spreading between 50% and 70% faster than other strains of the virus.
British scientists examined the frequency with which the new variant was detected, whether changes in its replication could make it more transmissible, and what data they showed on the correlation between the increase in the number of cases and the increase in the number of cases. detection of the new variant.
“All of these three branches of evidence really point in the same direction that this virus is a new variant that is slightly more transmissible than the existing virus,” said Peter Horby, a professor at Oxford University who is chairman of the Nervtag panel. , which advises the British government on new and emerging respiratory virus threats.
However, he added, more research was needed to find out how transmissible it is and the biology behind it. “We still don’t understand the exact biological mechanisms. There’s still a lot of uncertainty about exactly how it’s occurring, to what extent additional transmissibility.”
British scientists have been actively monitoring virus mutations and have sequenced the genome of 160,000 new coronavirus samples, or 10% of all Covid-19 cases in the country. All in all, British researchers say their work accounts for half of all coronavirus genomes sequenced worldwide since the start of the pandemic.
Examining the new variant, the researchers found that it had 23 mutations, 17 of which could have an effect on the behavior of the virus, including some on the spike protein that other research has found may help the virus enter cells. · Cells more effectively than previous variants. .
An image of the covers of British newspapers reporting on new coronavirus restrictions by British Prime Minister Boris Johnson.
Photo:
paul ellis / Agence France-Presse / Getty Images
Despite the findings, many researchers say more work is needed to find out if the changes have an impact in the real world.
“The new variant is worrisome, but we still know a lot about it,” said Angela Rasmussen, a virologist at the Center for Global Health Science and Security at Georgetown University. “I don’t think we can come to any conclusions about that, other than that we need to dig deeper into that.”
Among the questions that researchers need to probe, several said, is whether the new variant is more sticky and adheres to cells and enters them more easily than other variants. Scientists must also study whether cells infected with the new variants produce more viruses and whether infected animals transmit the virus to uninfected ones more easily.
“Molecular studies to accurately measure transmissibility have not been done,” said Bettie Steinberg, a virologist and provost at Northwell Health’s Feinstein Medical Research Institutes. “Viruses mutate all the time.”
It would not be the first time a new variant has brought other people together during the pandemic, health experts said. Earlier this year, another variant – which emerged in Europe and also had a spike-protein mutation – replaced the Wuhan original as the most prevalent in the world.
Laboratory studies showed that the European variant was better in cell infection and transmission between animals.
This variant, however, only had a change in spike protein that could affect its function, said Vineet Menachery, a coronavirus expert at the University of Texas medical branch. The protein helps the virus enter and infect cells.
President-elect Joe Biden received the first shot of the two-dose Pfizer-BioNTech Covid-19 vaccine during a televised event Monday. Photo: Leah Millis / Reuters
The new UK variant has almost two dozen mutations, according to the team that mapped it. Eight of these are found in the ear protein gene. Several of the mutations could affect transmission, Dr. Menachery said.
The scientists found in a separate study that similar protein-tip changes facilitated viral entry into cells in laboratory experiments, as well as transmission in animal models.
The scientists said they were unsure how a constellation of mutations would affect the virus’s ability to infect cells and spread, but said they doubt the changes would be enough to make current vaccines ineffective.
A Pfizer spokeswoman said the gene-based technology that produced her vaccine has the flexibility to alter the vaccine’s RNA sequence to cover new variants of the virus, should one arise that is not well covered by the vaccine. current.
Pfizer and its partner BioNTech SE have tested blood samples from people immunized with their vaccine to determine their ability to neutralize multiple mutant variants, the spokeswoman said. So far, companies have found consistent coverage of all tested variants.
Companies are generating data on how blood samples from people immunized with their vaccine can neutralize the new UK variant
—Sarah Toy and Bojan Pancevski contributed to this article.
Write to Daniela Hernandez at [email protected], Joanna Sugden at [email protected] and Betsy McKay at [email protected]
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