Explained: What are COVID-19 Variants? Why do They Occur?
COVID-19: It's only natural for viruses to mutate. It's the same with SARS-CoV-2. But what is the mechanism?
Reporter, Producer: Priyanka Rudrappa
Video Editor: Purnendu Pritam
New variants of coronavirus are spreading at an alarming pace and have put the world on alert.
What are these variants? How do they occur? What does this mean for the pandemic? Let's break it down for you.
How do COVID-19 Variants Occur?
It's only natural for viruses to mutate. It's the same with SARS-CoV-2 – the virus that causes COVID-19.
When a virus replicates or makes copies of itself, it has no impact on the virus' properties.
But sometimes, it changes a little bit. These changes are called "mutations."
A virus with one or several new mutations is called a "variant" of the original virus.
Sometimes, the virus mutates in a way that it helps survive and spread more easily.
For example, it can make the mutant more skilled at infecting cells or evading antibodies.
These variants can take over other strains and become dominant.
But how does the mutation occur? What is the mechanism?
COVID-19 Variants: The Science Explained
SARS-CoV-2 is a type of RNA virus, which mutates almost every time it replicates, unlike DNA viruses.
SARS-CoV-2's RNA, has a set of genetic instructions, which is basically a blueprint for its functioning.
But viruses can't replicate themselves. They have to hack into another organism cells and use their machinery
So, this virus gains access to our cells using its “corona” or a layer of protein spikes that fits into our cellular receptors like a lock and key.
This is how they enter the host cells and make multiple copies of their genomes.
But some inevitably make some errors in the blueprint. The error is called a mutation.
An accumulation of mutations that significantly alter the properties of a virus lineage would be a new variant.
The SARS-CoV-2 variants found in the UK, South Africa, Brazil and India are examples. All have higher transmission rates than earlier lineages.
COVID-19 Variants: What's the Concern?
Experts are concerned as the new mutations improve the virus’s spike protein, that helps the coronavirus particles enter cells.
If the mutations are left unchecked, we are only giving it more chance to quickly spread through a population.
If a set of mutations makes a variant dominant, it may be called a "variant of concern".
The Alpha, Beta, Gamma and Delta are all variants of concern.
Despite these worries, research shows that mutations in coronavirus occur at a much slower rate than in other viruses such influenza.
This is because coronaviruses proof-read after replication - this helps in reducing the number of errors that accumulate.
This is good news for scientists working on vaccines. In the case of flu, the vaccines tend to be ineffective in a year or two. This is not an issue for Covid yet.
But variants still pose a huge threat and need a solid plan to tackle them.
For now, the only way to limit this mutation is by cutting transmission.
Tracing their origins through genome sequencing, data sharing and studying efficacy of vaccines against the mutants is very important.
Meanwhile, what we can do is stick to social distancing norms, get vaccinated and follow all hygiene protocols.
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