By: Nour Hany
Ever since the new Coronavirus, the cause of the disease known as COVID-19, first appeared, the world has been experiencing new variants and multiple waves of the virus, leaving world scientists baffled as to what may come next.
In December 2020, a variant called Delta, crawled to the Indian state of Maharashtra. At first, it was not that remarkable; however, few months later, when it found its way to New Delhi, it turned into a disaster, with 30,000 daily cases in late April 2021. “Suddenly … it is dominant and completely sweeps away Alpha,” said Anurag Agrawal, leader of the Institute of Genomics and Integrative Biology in New Delhi. After it spread around the world, it was labeled as a "variant of concern" (VOC) on 11 May by the World Health Organization (WHO).
Up till now, there are four VOC identified by WHO: alpha (B.1.1.7), beta (B.1.351), gamma (P.1), and delta (B.1.617.2). The delta variant has multiple mutations, none of them is really understandable when it comes to its function; what scientists do know is that these mutations are a factor in "allowing the virus to bind to the cells of humans and helping the virus to escape some immune responses," said Deepti Gurdasani, a clinical epidemiologist at Queen Mary University of London.
Scientists and researchers all around the world are working on finding out what makes this specific variant extremely dangerous. "They are concentrating on a suite of nine mutations in the gene encoding spike; the protein that studs the virus’ surface and allows it to invade human cells. One important mutation, called P681R, changes an amino acid at a spot directly beside the furin cleavage site, where a human enzyme cuts the protein, a key step enabling the virus to invade human cells. In the Alpha variant, a mutation at that site made cleavage more efficient; a preprint published in late May showed Delta’s different change makes furin cleavage even easier. The researchers suggest this could make the virus more transmissible“.
In India, other coronavirus variants have been less successful than Delta, so what causes this difference? There is another type of mutation that might "thwart" immunity. “We think the 157/158 mutation is one of the hallmark mutations in Delta that has given it this more immune-evasion phenotype,” Trevor Bedford, a computational biologist at the Fred Hutchinson Cancer Research Center.
Delta is still a huge mystery that we know nothing about. It may take months for scientists to understand and learn more about this variant, as it has so many mutations, each responsible for a completely different role in strengthening it. “Delta has several mutations in the nucleocapsid protein, for example, which has many jobs, like a Swiss Army Knife protein,” said virologist David Bauer of the Francis Crick Institute.
It is now obvious that none of us humans could stop or have control over the coronavirus or its variants. It is really important, however, that we hurry up in getting vaccinated, especially in places where Delta strikes the most. It is believed that the variant could very much be controlled and that vaccination provides some sort of protection against the variant. “Anything that has happened at least twice in evolution is part of a pattern, I would be very unsurprised if we saw equivalent changes over the coming year or two,” says Katzourakis, an evolutionary virologist at the University of Oxford.
References
https://www.sciencemag.org/news/2021/06/delta-variant-triggers-dangerous-new-phase-pandemic
https://www.dw.com/en/fact-check-what-do-we-know-about-the-coronavirus-delta-variant/a-57949754