U.K. Says Virus Strain Afflicting London Spreads More Easily
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U.K. health officials raised the alarm about a variant of the coronavirus that’s spreading quickly across London and southeast England.
The variant of Covid-19 has almost two dozen mutations that may affect proteins made by the coronavirus, Patrick Vallance, the U.K.’s chief scientific adviser, said Saturday. It’s rapidly becoming the dominant strain in the capital and the southeast, he said.
Scientists have found mutations in areas of the genome “that are known to be associated with how the virus binds to cells and enters cells,” Vallance said in a press briefing alongside Prime Minister Boris Johnson. The changes “cause concern in terms of how the virus looks.”
Johnson said there’s no evidence that the variant is more lethal or causes more severe illness than the earlier strains, nor are there indications it will be less susceptible to Covid-19 vaccines that are being rolled out, though the data is still under review.
Yet it does appear to be as much as 70% more transmissible, and could increase the R value, the number of people infected by a person with the virus, by 0.4, Johnson said.
Viruses are typically genetically unstable, and their constant mutations give them opportunities to infect new organisms, as the coronavirus did last year when it likely jumped from animals to humans. Scientists expressed concern that the increasing spread of the pathogen, which has already infected more than 75 million people worldwide, may give it the chance to change into a more lethal form.
“We have to reduce transmission to prevent hospitalisations & deaths,” Jeremy Farrar, an infectious disease specialist and director of Wellcome, the U.K. research foundation, said on Twitter. “We also have to reduce transmission to reduce opportunity for virus to evolve & escape control.”
Changes in viruses have the potential to lead in different directions, curbing transmission and virulence but also possibly moving in a more severe direction, he wrote. It’s too early to know if it’s becoming more dangerous, he added. While many aspects of the pandemic have been predictable since the start of the year, “we may be entering a less predictable phase.”
Johnson initiated a new round of restrictions on Saturday as the U.K. reported 27,052 new cases, bringing the total to more than 2 million. The country reached 1 million cases on Oct. 31.
The prime minister imposed a lockdown on London and large parts of southeast England. He canceled plans to ease pandemic restrictions for five days over the holidays, and banned household mixing in London and the southeast while restricting socializing to just Christmas Day across the rest of England.
SARS-CoV-2 generally mutates at a slower pace than some other viruses because it has a self-correcting mechanism that keeps its genetic sequence relatively stable. But other variants in the coronavirus have been detected, including one in minks, which are susceptible to the virus, that was feared to be highly transmissible and was reported to the World Health Organization.
Millions of farmed mink were culled, although as of Nov. 20 the WHO said the most worrying strain linked to the animals is no longer circulating in humans.
Viral mutations are sometimes a cause for concern. Almost 20 years ago, scientists closely tracked mutations in a deadly strain of bird flu that killed or resulted in the cull of millions of birds worldwide, and was highly dangerous in the few people who became infected. The flu virus eventually faded without gaining the ability to spread easily from one person to another.
The coronavirus is already highly contagious. In the absence of virus control measures, each infected person frequently infects others. It can spread both from the noses and mouths of infected people in droplets and tiny particles called aerosols.
In certain conditions, like those in meat-packing plants, the virus has been known to spread among workers separated by more than 20 feet. Another danger is that the virus spreads from people who show no symptoms and may not realize themselves that they’re infected.
If mutations were to cause the virus to become more lethal, that might create even more concern. So far, more than 1.6 million people worldwide have died, and older people and those with chronic medical conditions have been at highest risk of severe symptoms and death.
Yet another concern is that mutation might lead to a virus that’s able to evade the immune response created by vaccines that are now rolling out.
“There are theoretical reasons to suspect some of the changes might alter some of the immune response, but there’s nothing that’s been seen to suggest that’s the case,” Vallance said.
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