Do other viruses have as many variants as SARS-CoV-2?,
published 2 days ago
Is COVID-19's rapid evolution unusual, or do other viruses have as many variants?
Like influenza viruses, RSV, enteroviruses, and rhinoviruses, which cause the common cold, SARS-CoV-2 carries its genetic information on a strand of RNA. And compared with other RNA viruses, "[the mutation] rate in SARS-CoV-2 is not particularly remarkable," said Katie Kistler, a postdoctoral researcher who studies viral evolution at the Fred Hutchinson Cancer Research Center in Seattle. In fact, it's similar to the mutation rate of other common RNA viruses, such as influenza and other common coronaviruses that cause cold-like symptoms, she told Live Science.
The bottom line on mutations: SARS-CoV-2 isn't mutating at an unusually fast rate. But other factors in play, like the virus's high transmissibility, its transition from an animal host to humans, and the development of new treatments and vaccines, may have ramped up the number of SARS-CoV-2 variants we've seen over a short time.
The rapid changes of SARS-CoV-2 may also be related to its recent jump to humans. Until 2019, the virus was adapted to infect an animal host, most likely bats. Initially, "the virus needs to adapt to infect humans rather than bats," Kistler said. "There are a lot of beneficial mutations available to the virus during that [transition] phase." Afterward, a virus's adaptive evolution slows down a bit.
Finally, the changes we see in SARS-CoV-2 are also partly driven by the rapid development of vaccines and treatments designed to stop it. Compared with the early days of the pandemic, there's now much more selection pressure on the virus to escape the pharmaceutical measures designed to defeat it, Das told Live Science. Now we have multiple vaccines: antibody cocktails, convalescent plasma therapy and two drugs on the market to combat COVID. That's a lot of new pressures driving selection of the virus. Some of the mutations that stick are now the ones that will help the virus avoid these challenges.
Prijevod
Imaju li drugi virusi toliko varijanti kao SARS-CoV-2?,
objavljeno prije 2 dana
Je li brza evolucija COVID-19 neobična ili drugi virusi imaju isto toliko varijanti?
Poput virusa gripe, RSV-a, enterovirusa i rinovirusa, koji uzrokuju prehladu, SARS-CoV-2 prenosi svoje genetske informacije na niti RNA. U usporedbi s drugim RNA virusima, "[stopa mutacije] u SARS-CoV-2 nije osobito značajna", rekla je Katie Kistler, postdoktorska istraživačica koja proučava evoluciju virusa u Centru za istraživanje raka Fred Hutchinson u Seattleu. Zapravo, slična je stopi mutacije drugih uobičajenih RNA virusa, kao što su gripa i drugi uobičajeni koronavirusi koji uzrokuju simptome slične prehladi, rekla je za Live Science.
Zaključak o mutacijama: SARS-CoV-2 ne mutira neobično brzom brzinom. No, drugi čimbenici u igri, kao što je visoka prenosivost virusa, njegov prijelaz sa životinjskog domaćina na ljude i razvoj novih tretmana i cjepiva, možda su povećali broj varijanti SARS-CoV-2 koje smo vidjeli tijekom kratkog vremena. vrijeme.
Brze promjene SARS-CoV-2 također mogu biti povezane s njegovim nedavnim skokom na ljude. Do 2019. godine virus je bio prilagođen zarazi životinjskog domaćina, najvjerojatnije šišmiša. U početku se "virus mora prilagoditi da zarazi ljude, a ne šišmiše", rekao je Kistler. "Postoji mnogo korisnih mutacija dostupnih virusu tijekom te [prijelazne] faze." Nakon toga, adaptivna evolucija virusa se malo usporava.
Konačno, promjene koje vidimo u SARS-CoV-2 također su dijelom potaknute brzim razvojem cjepiva i tretmana dizajniranih da ga zaustave. U usporedbi s ranim danima pandemije, sada je mnogo veći selekcijski pritisak na virus kako bi pobjegao od farmaceutskih mjera koje su osmišljene da ga poraze, rekao je Das za Live Science. Sada imamo više cjepiva: koktele s antitijelima, rekonvalescentnu terapiju plazmom i dva lijeka na tržištu za borbu protiv COVID-a. To je mnogo novih pritisaka koji pokreću selekciju virusa. Neke od mutacija koje se zadržavaju sada su one koje će pomoći virusu da izbjegne ove izazove.
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