Are mutations making COVID-19 more infectious in humans?

*D614G variant of virus is so dominant that it is the pandemic now, say experts

*No evidence Coronavirus has mutated to make patients more or less sick ─Research

Isola Moses | ConsumerConnect

There are concerns about the recent observation in regard to the likely mutations of the novel Coronavirus disease (COVID-19) in infected people.

The reported changing virus is currently being studied at the University College Hospital in London, United Kingdom (UK).

Mutation has been described as “a change in genetic material; a random change in a gene or chromosome resulting in a new trait or characteristic that can be inherited. “Mutation can be a source of beneficial genetic variation, or it can be neutral or harmful in effect.”

As regards genetic mutation, it is said to be one that involves “a change in a single base or base pair of the nucleotides in a gene, occurring as a result of addition, deletion, or substitution,” according to a medical reference book.

The Coronavirus that is threatening several billions of peoples around the world right now is said to be different from the Coronavirus that first emerged in China, according to BBC report.

Specifically, Sars-Cov-2, the official name of the virus that causes the disruptive COVID-19, and continues to blaze a path of destruction across the globe, is mutating, said the report.

However, as scientists have spotted thousands of mutations, or changes to the virus’s genetic material, only one has so far been singled out as possibly altering its behaviour.

Report stated that the crucial questions about this mutation are: Does this make the virus more infectious – or lethal – in humans? And could it pose a threat to the success of a future vaccine?

This Coronavirus is actually changing very slowly compared with a virus-like flu. With relatively low levels of natural immunity in the population, no vaccine and few effective treatments, there is no pressure on it to adapt.

Thus, it is doing a good job of keeping itself in circulation as it is, report further said.

The notable mutation ─ named D614G, and situated within the protein making up the virus’ ‘spike’ it uses to break into our cells ─ appeared sometime after the initial Wuhan outbreak, probably in Italy.

It was learnt that it is now seen in as many as 97% of samples around the world.

In terms of the evolutionary edge of the development, it is aid that the question is whether this dominance is the mutation giving the virus some advantage, or whether it is merely coincidental.

According to report, viruses do not have a grand plan. They mutate constantly and while some changes will help a virus reproduce, some may hinder it. Others are simply neutral.

Dr. Lucy van Dorp of University College London said of the observation, that they are a “by-product of the virus replicating,” adding that they “hitch-hike” on the virus without changing its behaviour.

The mutation that has emerged could have become very widespread just because it happened early in the outbreak and spread ─ something known as the “founder effect”. This is what Dr. van Dorp and her team believe is the likely explanation for the mutation being so common. But this is increasingly controversial.

Dr. Thushan de Silva of the University of Sheffield, UK, also explains that a growing number, perhaps the majority of virologists now believe, that there is enough data to say this version of the virus has a “selective advantage”, that is an evolutionary edge over the earlier version.

However, there is yet no enough evidence to say that “it is more transmissible” in people, it is “not neutral,” states Dr. de Silva.

When studied in laboratory conditions, the mutated virus was better at entering human cells than those without the variation, submitted Professors Hyeryun Choe and Michael Farzan, at the Scripps University in Florida, United States (US).

According to them, changes to the spike protein the virus uses to latch on to human cells seem to allow it to “stick together better and function more efficiently”.

But that’s where they drew the line, said the report.

Prof. Farzan said the spike proteins of these viruses were different in a way that was “consistent with, but not proving, greater transmissibility”.

On the lab result proof, at the Genome Technology Centre at the New York University, Dr Neville Sanjana, who normally spends his time working on gene-editing technology Crispr is said to have gone a step further.

Report indicates that his team edited a virus so that it had this alteration to the spike protein and pitted it against a real Sars-CoV-2 virus from the early Wuhan outbreak, without the mutation, in human tissue cells.

The results, he believes, prove the mutated virus is more transmissible than the original version, at least in the laboratory.

Dr. van Dorp, nonetheless, points out “it is unclear” how representative they are of transmission in real patients.

But Prof. Farzan says these “marked biological differences” were “substantial enough to tilt the evidence somewhat” in favour of the idea that the mutation is making the virus better at spreading.

Outside a Petri dish, there is some indirect evidence this mutation makes coronavirus more transmissible in humans.

Two studies have suggested patients with this mutated virus have larger amounts of the virus in their swab samples. That might suggest they were more infectious to others, report stated.

Further still, the report explained that they did not find evidence that those people became sicker or stayed in hospital for longer, though.

On the whole, being more transmissible does not mean a virus is more lethal ─ in fact, the opposite is often true.

There is no evidence this coronavirus has mutated to make patients more or less sick.

But even when it comes to transmissibility, viral load is only an indication of how well the virus is spreading within a single person.

It does not necessarily explain how good it is at infecting others, according to the report.

The mutation is the pandemic

When it comes to looking at the population as a whole, the study noted that it is difficult to observe the virus becoming more (or less) infectious.

Its course has been drastically altered by interventions, including lockdowns, stated the report.

Prof. Korber, however, says the fact the variant now appears to be dominant everywhere, including in China, indicates that it may have become better at spreading between people than the original version.

Whenever the two versions were in circulation at the same time, the new variant took over.

In fact, the D614G variant is so dominant, it is now the pandemic. And it has been for some time ─perhaps even since the start of the epidemic in places such as the UK and the east coast of the US.

Report added that although evidence is mounting that this mutation is not neutral, it does not necessarily change how we should think about the virus and its spread as of now.

On a more reassuring note, most of the vaccines in development are based on a different region of the spike so this should not have an impact on their development.

And there is some evidence the new form is just as sensitive to antibodies, which can protect you against an infection once you have had it ─ or been vaccinated against it.

Nevertheless, the report notes that since the science of COVID-19 is so fast-moving, this is something all scientists, wherever they stand on the meaning of the current mutations, will be keen to keep an eye on going forward.

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