Why are new coronavirus variants emerging in the United States?



Almost a year after the start of the pandemic, Covid-19 is spreading at record rates in the United States and, with it, new variants of the virus are emerging. Last week, researchers in Ohio said they identified two variants unique to Columbus.

Experts agree that it is not surprising that new variants have appeared in the United States, but point out that the uncontrolled transmission of the virus in the country offers many opportunities to mutate. The best way, therefore, to crack down on the new variants is to stop the spread, they say.

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“The only way to [stop emergence of new variants] is to stop the spread of the virus, ”said Ben Bimber, a research professor at the Oregon University of Health and Sciences.

If there are more people infected, there are simply more viruses and there is more opportunity to mutate.

“Every time the virus replicates, it’s an opportunity to mutate,” he said. “If there are more people infected, there are just more viruses and there is more opportunity to mutate.”

When the coronavirus infects an individual, it enters cells and copies itself. “Every time the virus copies itself, there is a chance to introduce errors,” Bimber said. “If the virus replicates in humans, it will slowly accumulate mutations.”

Often these mistakes, or mutations, don’t make sense. But in some cases, they can give the virus a survival advantage – making it more contagious, for example, or more resistant to treatments or vaccines. On the other hand, certain mutations can weaken the virus.

It is not known how the two variants recently identified in Ohio will affect the behavior of the virus.

The results of these variants were published last Friday on the online preprint server BioRxiv, which means they have yet to be peer reviewed. In the study, researchers analyzed the genetic sequences of more than 220 coronavirus samples obtained in the Columbus area from April 2020 to early January 2021.

One of the variants identified in Ohio contains a mutation on the virus spike protein called N501Y – the same mutation found in the most contagious UK variant, as well as the South African variant, Dr. Dan Jones, vice president of the division of molecular pathology at Ohio State University’s Wexner Medical Center, said at the press conference last Wednesday. The variant did not come from someone abroad; rather, by analyzing other small changes in the variant’s genetic code, the researchers were able to determine that it emerged independently, in the United States.

William Hanage, associate professor of epidemiology at Harvard TH Chan School of Public Health, said he was not surprised by the detection of new variants, especially the one with the N501Y mutation, “due to the fact that this has happened so often. “As well as emerging in the UK and South Africa, this particular mutation has also been detected in Brazil.

The other variant contained a combination of three mutations that had not been seen together before, the researchers said. While the N501Y mutation was only found in one sample, this variant, with three mutations, quickly became predominant in the samples the researchers tested in December and January.

Jones told NBC News that vaccination is essential both to stop the spread of variants and to reduce the chances of new variants emerging.

“Plus your pool of [susceptible] patients, the more chance a mutation has to survive and emerge, ”he said. “It has to pass from person to person, so if you don’t get a lot of infection in the population [because of vaccination], then even a large mutation may go away, because the infected person does not pass the virus on to anyone else. “

Even “having optimal adaptation and pathogenic change in the virus is of no use if it continues to meet a wall of vaccinated people,” Jones added.

The Centers for Disease Control and Prevention said they were “aware” of the Ohio variants and released the same statement they made on Jan.8, following a controversial report from the group of White House coronavirus work which speculated that an American variant could drive the recent surge in cases in the country.

According to this statement, while it is highly probable that there are many variants evolving simultaneously across the world, the CDC has “not seen the emergence of a particular variant in the United States, as has been seen with the emergence of B.1.1.7. in the UK or B.1.351 in South Africa. “

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However, the statement noted “there is a strong possibility that there are variations in the United States; however, it could take weeks or months to identify if there is a single variant of the virus that causes Covid-19 fueling the outbreak in the United States, similar to that in the United Kingdom.

New variants are expected and not all of them are of concern, said Angela Rasmussen, a virologist at Georgetown University’s Center for Global Health Science and Security.

“We should be concerned when a variant is accompanied by epidemiological evidence such as that seen in the UK” – she said, referring to the spike in cases being considered as the variant in that country became widespread – or if there is a significant association with an increased severity of the disease. “

But “whatever variants emerge, we need to focus on reducing the transmission of all variants,” Rasmussen said. This means wearing a mask, avoiding crowds, and practicing good hand hygiene.

Bimber agreed it was too early to draw any conclusions about the variants detected in Ohio.

“It’s a very fast moving space and it takes time to really assess the effects of these” new variants, “he said. “It won’t be the last, and there will certainly be new variants that emerge in the virus as it infects more people.”

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