How genome sequencing helps track viral evolution and where the UK COVID variant fits in – Times Now

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Only weeks after vaccine breakthroughs sparked hopes of an end to the pandemic, Britain has sounded the alarm over a new highly contagious variant of COVID-19 circulating within the country. Prime Minister Boris Johnson has responded to the threat by implementing Tier 4 restrictions the most stringent in large parts of southern and eastern England while over forty countries have already suspended entry of flights from the UK into their borders.

Since China published the full genomic sequence of the virus found in Wuhan, geneticists have been hard at work identifying the various strains of COVID-19 across the world and comparing them with their Wuhan ancestor discovered in mid-November 2019.

When a virus passes between one carrier to another, there may only be very subtle changes in the genome that take place. However, as it travels over larger numbers of carriers and across distances, these genomic differences become larger and more noticeable. By analysing the changes in the genome, researchers can create a high-resolution picture of how the virus has evolved in real-time and, perhaps, more importantly, identify the key transmission chains along which it has travelled. This information can prove vital in informing policy decisions and appropriate safety protocols.

As far as mutations go, SARS-CoV-2, being an RNA virus, behaves similarly to other viruses that cause Ebola, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome (SARS) and influenza. These viruses are typically more prone to replication errors mutations than DNA viruses. Scientists have determined that SARS-CoV-2 has a fairly predictable evolution rate, mutating on average twice a month. Through sequencing, researchers can identify sub-lineages of the viruses much like outlining the branches of a tree.

Epidemiological experts agree that most mutations are unlikely to change the nature of the virus much, if at all, as it relates to transmissibility and severity of the symptoms caused. But there always remained a risk of a mutation which could make a real difference to the way the virus that causes COVID-19 behaves.

Early data indicates that, with, reportedly, 20 different mutations, the new variant found in Britain could, in fact, be what they have warned about. It is difficult to identify exactly how such variants come about. In some cases, it could just be through sheer luck.

But as immunity within populations builds either through vaccination or otherwise, researchers expect the virus to gain further practical mutations that enable it to spread more rapidly or hide from our immune systems. The viral strain now prevalent in Britain is particularly worrying in that its mutations affect the way the virus attaches itself to human cells and infects them. It is important to note though, that currently there is no evidence to suggest that it causes more severe symptoms.

Similarly, experts have been quick to reassure communities that there is little to suggest that the new variant may be more resistant to the vaccines developed, or in development. While it is important to pay close attention to these mutations, researchers have noted that it often takes years, not months, for a virus to mutate to a point where vaccines are rendered ineffective. However, with the virus, reportedly, spreading more aggressively through the UK's population than previous strains, this may warrant a redoubling of vaccination efforts.

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How genome sequencing helps track viral evolution and where the UK COVID variant fits in - Times Now