These coronavirus variants are keeping scientists awake at night - CNN - 0 views
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One, first identified in southeast England, has now shown up in at least 50 countries and appears to be spreading more efficiently than older variations of the virus. Its appearance has frightened political leaders, who have closed borders and imposed travel restrictions in attempts to curb its spread.
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So far, none has done what scientists most fear and mutated to the point that it causes more severe disease, or evades the protection provided by vaccination. While some of the new variants appear to have changes that look like they could affect immune response, it7;s only by a matter of degree.
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At the top of the list for researchers in the US is the B.1.1.7 variant first seen in Britain. The US Centers for Disease Control and Prevention warned last week it could worsen the spread of the pandemic.
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Plus there7;s evidence people infected with the B.1.1.7 variant have what7;s known as a higher viral load -- they have more virus reproducing in their bodies. That makes sense if the variant infects cells more easily, because viruses hijack the cells they infect, turning them into virus factories. More infected cells equal more virus.
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Biologist Michael Worobey of the University of Arizona said he7;s found evidence B.1.1.7 was imported at least five separate times to the US, and likely many more. "It is striking that this lineage may already have been established in the US for some 5-6 weeks before B.1.1.7 was first identified as a variant of concern in the UK in mid-December,"
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That should reassure people, Nussenzweig said. The human immune system adapts very well to viral mutations, he said, and produces hundreds of different antibodies that can attack coronavirus.
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Finally, there7;s a new variant seen in California. "We don7;t know yet what the significance of that one is," said Armstrong. It also has a mutation in the receptor binding domain of the spike protein. The new California variant is called L425R and while it7;s being found commonly, it7;s not yet clear if it7;s more transmissible.