As the emergence of new variants such as XBB, BQ.1 and more make for concern around the globe, many wonder – why do Covid-19 variants keep coming up so frequently?
After the scourge of Delta in India last year, the Omicron variant caused a third, albeit ‘milder’ wave, in India. And now, experts and health authorities are watching out for a sub-variant of Omicron – dubbed XBB – which has displayed ‘immunity-evasive’ properties and is said to circumvent even the bivalent vaccines.
News18 explains how variants come up, and whether we should be concerned about these:
A Constantly Mutating Virus
According to a report by CNN, if and when a virus replicates in a host body, it mutates constantly. The more people who become infected, the more likely the virus will evolve through a process known as mutation.
“The longer someone has that virus, and the longer that virus has to deal with people’s antibody responses, the more likely variants will emerge,” Penny Moore, a virus expert at South Africa’s National Institute for Communicable Diseases told CNN.
Compromised immunity in patients – due to HIV or immuno-suppressant drugs – may cause the virus to exist in the body for long, giving it ample time to mutate. However, the virus is infecting and mutating people all over the world on any given day, the report explains, and when those mutations give the virus an advantage, such as the ability to replicate faster or hide from the immune system, that version will outcompete others.
Vaccination Important
“The longer someone has that virus, and the longer that virus has to deal with people’s antibody responses, the more likely it is that variants will emerge,” Moore said. This is why public health officials around the world are urging everyone to get fully vaccinated as soon as possible. People who do not become infected do not cook a constantly changing virus in their bodies.
“It’s the only way we are going to be able to get rid of the variants, is to lower the number of infections,” Moore told CNN.
The ‘Hiding Virus’
The expert further explained: “All viruses have a receptor that allows them to attach to a cell, and this is where the infection process begins. And in some cases, how well that virus binds to the host cell receptor really changes the game.”
According to her, a virus with a binding advantage simply means it has a much better chance of infecting cells. As a result, viruses carrying such a mutation are more likely to replicate and spread than viruses without the mutation. “That’s a lot of what we’re seeing now with the variants,” Moore said.
Moore said another advantage is the ability to become more invisible to the human immune system, which alludes to immune evasion or antibody escape mutations.
“The virus has changed its coat as a result of one of these mutations, allowing it to become less visible. It’s as if it’s hiding from the immune system under an umbrella because it’s managed to mutate its coat in some way.”
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