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COVID-19 mutation may have helped it transmit, infect at a higher rate: study

WATCH: A timeline of how COVID-19 spread around world.

The coronavirus is continuing to mutate, and a recent study believes one of the lastest strains could be more contagious.

The study out of Houston was published Wednesday on the preprint server MedRxiv. It has not been peer-reviewed, meaning the research has yet to be evaluated and should not be used to guide clinical practice.

Read more: Mutation that made coronavirus more infectious may make it vulnerable to vaccines, study says

The research found the mutation did not make COVID-19 deadlier, but with the spike in coronavirus cases across the U.S. and Canada, the virus has had opportunities to change and become more infectious.

David Morens, a virologist at the National Institute of Allergy and Infectious Diseases, told the Washington Post, that the findings could mean COVID-19, through its mutations, is responding to public health interventions, such as mask-wearing and social distancing.

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“Wearing masks, washing our hands, all those things are barriers to transmissibility or contagion, but as the virus becomes more contagious, it statistically is better at getting around those barriers,” Morens said.

But he stressed that this is still a new study and the research should not be over-interpreted.

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About the study

The study’s researchers said they sequenced the genomes of 5,085 strains of SARS-CoV-2, the virus that causes COVID-19, and examined it over the two pandemic waves in Houston, an ethnically diverse region with seven million residents.

The first coronavirus wave took place from March 5 to May 11. The second was from May 12 to July 7.

The authors said many different strains of the virus entered Houston initially. But when the city went from a small first wave in March to a much larger second one in late June, almost every coronavirus sample contained a particular mutation on the virus’s surface.

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Read more: 2nd coronavirus wave in U.S. hits plateau, but future still uncertain

The research found that “virtually all strains” in the second wave have a “Gly614 amino acid replacement in the spike protein,” which is linked to increased transmission and infection.

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Strains with the Gly614 amino acid variant represented 71 per cent of SARS-CoV-2 sequenced in March (the early part of wave one), 82 per cent a few weeks later and then 99.9 per cent in the second wave, the study found.

People infected with the mutated strain had higher loads of the virus in their upper respiratory tracts, a potential factor in making the strain spread more effectively, the authors said.

They added that the severity of each case depended on whether the patient had underlying health conditions.

The rise of this contagious strain of COVID-19 may have contributed to a spike in cases in the Houston area, the study concluded.

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Levon Abrahamyan, a virologist at the University of Montreal, said the study is “very important” as there are a large number of samples to examine.

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However, he said, it has limitations.

“It’s hard to take into account variables like ethnic background, age, economic status, medical care … All of this can have an influence on the outcome,” he explained.

So, what does this mean?

Morens said if the findings turn out to be correct, the mutation may have implications for a vaccine.

If someone receives a coronavirus vaccine, there is a “possibility” that the virus will find a way to get around the immunity, he said.

Read more: Canada signs deal to obtain 20M doses of Oxford coronavirus vaccine candidate

Abrahamyan said if the virus does have the ability to transmit or infect more easily, this could mean that, on a global level, we would be dealing with a strain of the coronavirus that may change every few years, like influenza.

“Every year we may have a new strain, which means we may have to have a new vaccine and change it every few years,” he said.

Mutations happen

Ever since COVID-19 emerged in Wuhan, China last year, thousands of mutations have been observed, scientists said.

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“It’s absolutely normal for a virus to mutate. They do so at a very high rate, too, which is why they are so adaptable; they have the ability to adapt to new situations and new hosts. This is why we have this new coronavirus,” Abrahamyan said.

He added that even though the coronavirus mutates quite frequently, it still does not do so as fast as other viruses like influenza and HIV.

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“This is not the first report about this mutation. A change in a spike protein is important for the virus to bind to the host cell,” Abrahamyan said.

Abrahamyan said what could make this coronavirus mutation different is that scientists are speculating the coronavirus could have a higher “fitness,” meaning, it can increase its chance to attach and enter the human body or multiply.

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But in terms of its ability to get through a mask, he said he doesn’t buy it.

Read more: Wearing a mask may reduce how sick you get from coronavirus

“I don’t believe in that speculation. It can’t change its ability to get through a mask — the size is still the same.,” he said. “(Instead) we’re talking about its higher fitness level for this mutant strain of coronavirus … Its mobility could be higher.”

Abrahamyan stressed until there is a safe vaccine available, wearing a mask, washing your hands and practising physical distancing is still the best way to safeguard against spreading COVID-19.