The virus often mutates by simply deleting small pieces of its genetic code. The mutations "disguise" the virus from antibodies.
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00:00The novel coronavirus has recently developed a number of worrisome mutations, resulting
00:05in multiple new variants popping up around the world.
00:08A new study sheds light on how the virus mutates so easily, and why these mutations help it
00:14escape the body's immune system.
00:16The beauty of this story is it's quite complex, but it's really rather simple.
00:27The study researchers found that SARS-CoV-2, the virus that causes COVID-19, often mutates
00:33by simply deleting small pieces of its genetic code.
00:37Although the virus has its own proofreading mechanism that fixes errors as it replicates,
00:43the deletions get around this.
00:45So what deletions do is not only alter one site, but they can alter a string of sequential
00:50letters in a row.
00:51And so you can't proofread against that, and you can alter a number of amino acids that
00:57build up that protein.
00:59And so it does represent a way that the virus can quickly adapt.
01:02Oh, it's devilishly clever.
01:05For their study, the researchers used a database to analyze nearly 150,000 genetic sequences of
01:12SARS-CoV-2.
01:13They found that these deletions frequently show up in similar spots on the genome.
01:18And these deletions started to line up to very distinct sites, and so that's why we've
01:23called them recurrent deletion regions, because we kept seeing them over and over and over
01:26again from viruses from different places at different times in genetically distinct
01:32viruses.
01:33Possibly, these deletions were leading to the escape or the evolution away from antibodies
01:38that are binding it.
01:39This would be a way to get around that, because the antibodies won't be able to recognize.
01:43Yeah, because remember, the key thing in biology is shape, and precise little changes in shape,
01:50even in a big molecule, can have really, really big effects, right?
01:56So perfectly attuned to recognize shape, small movement, and this thing doesn't see this
02:02anymore.
02:03I mean, one missing building block out of about 1,200 can knock out the binding of antibodies
02:09that are potently neutralizing.
02:10So you're looking at, you know, less than a 1%, you know, change there.
02:15Small changes in biology can have massive effects, and that's why we have to think about antibiotic
02:22resistance and anti-barrel drug resistance.
02:25And that's where it's really hard whenever you're trying to describe this, because it's
02:31hard to show something which is gone, right?
02:35Absence is hard to show.
02:38But these tiny little absences have a big, big effect.
02:43Does it seem like the main goal from the evolution perspective is to sort of escape the immune
02:49system, and this transmissibility might be like a secondary factor, or we don't, like a beneficial
02:54side effect, but we don't really.
02:56The virus has evolved to replicate efficiently, and it'll evolve around anything that gets in
03:01its way, or go extinct.
03:04Evolution finds these sweet spots, and this is a pretty good virus, right?
03:08What it's doing is, every single time it's replicated, think of the millions of people
03:11that virus is replicating in the world each day, right?
03:15Just anything that we can do to dampen the number of times it replicates, just like Kevin
03:20said, will buy us a little bit of time.
03:25Coming up with the tools, now that we know that they're important and that they can alter
03:28the immunogenicity of the molecule the way that some antibodies bind it, and understand
03:34if there's clinical changes that are associated with that, and that's in some ways what happened
03:38with the discovery of the variants from South Africa and from the United Kingdom, both of which
03:44have deletions.
03:45Will we see something happen like we do with flu vaccines, that these need to be reformulated
03:51frequently?
03:52You know, it's not going to be an all-or-nothing where one day, you know, the virus can be blocked
03:58by a vaccine, and the next day it's gone.
04:00It's a continuum.
04:01But you still have something that's 90 or 85 percent efficacious, which I think at the
04:06start of this pandemic we'd all sign up for.
04:08It's not just going to be this virus.
04:09It'll be the next virus, and the next virus, and the next virus, and the next virus.
04:13They will continue to emerge.
04:15They will continue to evolve.
04:17And we continually have to play cat and mouse and stay one step ahead of them.
04:23The results underscore the importance of closely monitoring the virus' evolution by tracking
04:28these deletions and other mutations.
04:31The findings also show why it's important to wear a mask and implement other measures
04:35to prevent the virus from spreading.
04:38The more people it infects, the more chances it has to replicate and potentially mutate.