On Monday, Nature released a report showing that we are slowly but surely finding out the origin of the Sars-CoV-2 virus that causes the coronavirus disease (Covid-19). The report deals with two related findings about the virus that came, not from the field, but from the freezer. There have been a lot of big stories about the virus in the last 11 months, so this is something.
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First, according to Nature, in two Shamel horseshoe bats captured in Cambodia in 2010 and stored in a freezer in a laboratory, scientists found a coronavirus that appears to be related to Sars-CoV-2. Coronaviruses are a family of RNA viruses (coronaviridae) that are known to cause disease in humans, other mammals, and birds. Some of these are harmless; some common colds are caused by coronavirus. But some, as we’ve discovered, can be dangerous. Severe acute respiratory syndrome (SARS), the Middle East respiratory system (Mers), and Covid-19 are serious illnesses caused by coronavirus. Mers, for example, killed about a third of the people it infected (866 out of 2,519), but most experts admit that this is perhaps an overestimate. Many cases of Mers may have been mild, even undetected, and caused no more than minor illness or nothing at all. Nature reports that the virus found in the Cambodia lab is being sequenced.
Second, the journal reports that a Japanese laboratory found a virus that shares 81% of its genome with Sars-CoV-2 in frozen samples from a Japanese bat captured in 2013. That’s not much. There is a 99% similarity within a species. But if you travel further up the chain (to, say, gender), the divergence widens. For example, humans and chimpanzees are from the same family (and also subfamily), Hominidae (and Homininae), and our genome is 96% similar to that of a chimpanzee. In general, scientists believe that a genomic similarity greater than 95% can help them link two species in an evolutionary time frame. The advantages of doing this with Sars-CoV-2 are clear: it can shed light on where the virus came from, even discovering whether there was an intermediary in its transmission from bats to humans.
Interestingly, the Nature report says that the two findings, in Cambodia and Japan, may well mean that “undiscovered relatives of Sars-CoV-2 could be stored in laboratory freezers,” quoting Aaron Irving, a researcher at the University of Zhejiang in Hangzhou, China.
The report came one day when a third vaccine candidate, AstraZeneca / Oxford, published interim results showing 90% efficacy of the vaccine when administered as a half dose followed by a full dose, and 62% effective when administered. like two full doses. . The overall efficacy was 70.4%, which would have been considered high in any context other than the current one: the study results are published following the results published by Pfizer / BioNTech and Moderna showing an efficacy of 95% of your own vaccine. candidates. The AstraZeneca / Oxford vaccine is a vector vaccine, which uses a virus that causes the cold in chimpanzees to carry a piece of genetic material from the spike protein of the Sars-CoV-2 virus to trigger an immune reaction in the body. The vaccine requires normal refrigeration, which means it will be easier to transport than Pfizer’s. And a 70% success rate is not bad, most flu vaccines have a success rate of around 50%.
The good news for India is that the Serum Institute of India (SII), the world’s largest vaccine manufacturer, has an agreement with AstraZeneca to manufacture the vaccine in India (and, in fact, risked the vaccine’s success in get a head start). The company has said that 50% of the vaccines it makes will be for the local market. This means that if UK regulators approve the use of the vaccine, Indian regulators can do the same. If all this happens, the first doses of the vaccine may be available in India before the end of the year.
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