New ‘Omicron’ variant raises concerns, but vaccines may still work

Scientific experts from the World Health Organization warned on Friday that a new variant of the coronavirus discovered in southern Africa was a “worrying variant», The most serious category that the agency uses for such monitoring.

The designation, announced after an emergency meeting of the health body, is reserved for dangerous variants that can spread quickly, cause serious illness or decrease the effectiveness of vaccines or treatments. The last variant of the coronavirus to receive this label was Delta, which took off this summer and now accounts for almost all of the Covid cases in the United States.

The WHO has said the new version, named Omicron, carries a number of genetic mutations that could allow it to spread quickly, possibly even among those vaccinated.

Independent scientists agreed that Omicron deserved urgent attention, but also stressed that more research is needed to determine the extent of the threat. While some concern variants, like Delta, lived up to the initial concerns, others had limited impact.

“Epidemiologists are trying to say, ‘Easy, tiger,'” said William Hanage, an epidemiologist at Harvard TH Chan School of Public Health. “It could be bad. It could be very bad. But we don’t know enough to move this tape forward.

Dr Hanage and other researchers said the vaccines would most likely protect against Omicron, but more studies are needed to determine how much the effectiveness of the injections can be reduced.

As the coronavirus replicates inside humans, new mutations are constantly appearing. Most do not give the virus any new benefit. When disturbing mutations appear, the World Health Organization uses Greek letters to name the variants. The first “worrying variant”, Alpha, appeared in Britain in late 2020, soon followed by Beta in South Africa.

Omicron was first discovered in Botswana, where researchers at Botswana’s Harvard HIV Reference Laboratory in Gaborone sequenced coronavirus genes from positive test samples. They found samples sharing around 50 mutations never found in such a combination before. So far, six people have tested positive for Omicron in Botswana, according to an international database of variants.

Around the same time, South African researchers came across Omicron in a cluster of cases in Gauteng province. As of Friday, they had listed 58 Omicron samples in the variant database. But to a press conference On Thursday, Tulio de Oliveira, director of the Center for Epidemic Response & Innovation in South Africa, said that “nearly two or three hundred” genetic sequences from Omicron cases would be released in the coming days.

WHO has called for increased surveillance of the variant and laboratory experiments to better understand its biology.

“This variant surprised us,” Dr de Oliveira said at the press conference. “But the full meaning is still uncertain.”

Dr de Oliveira and colleagues have called on the WHO to hold an emergency meeting on the variant on Friday for two reasons: mutations at Omicron and what appears to be an alarming spread in South Africa.

Researchers have found more than 30 mutations in a protein, called a spike, on the surface of the coronavirus. The spike protein is the primary target for antibodies that the immune system produces to fight a Covid-19 infection. So many mutations have raised concerns that the Omicron tip might escape antibodies produced by a previous infection or vaccine.

Dr de Oliveira and his colleagues determined a quick way to assess the speed at which Omicron was spreading in South Africa. Although sequencing a virus’s entire genome is slow, scientists have discovered how to identify Omicron with a standard nasal swab test known as PCR.

The tests are quick because they only look for two of the 29 genes in the coronavirus – the spike gene and another gene called a nucleocapsid. Thanks to its new mutations, Omicron does not test positive for the spike gene. So researchers could simply look for samples that are positive for the core but negative for the peak.

As it turned out, samples with negative peaks were on the increase in South Africa, suggesting that Omicron had a competitive advantage over Delta, which was so far the dominant variant in the country.

“It makes us fear that this variant is already circulating quite widely in the country,” said Richard Lessells, an infectious disease specialist at the University of KwaZulu-Natal in Durban, South Africa, at the press conference of Thursday.

Dr de Oliveira warned that South Africa, where less than a quarter of the population is fully vaccinated, could see an increase in hospitalizations unless the country stops Omicron from further multiplying in super-spread events. “We would really like to be wrong on some of these predictions,” he said.

Countries in Europe as well as the United States and Canada have been among those banning flights from South Africa and several other African countries. But Omicron has already been spotted in Hong Kong and Belgium, and may well be in other countries outside of Africa as well.

Theodora Hatziioannou, a virologist at Rockefeller University in New York, said the distinctive mutations in Omicron raise the possibility that it first evolved inside the body of an HIV-positive person, whose immune system was maybe too weak to fight it quickly. “Your answers are just not as good,” said Dr Hatziioannou.

Instead of being cleared within days, the virus may have lingered in that person for months, spending time gaining the ability to escape antibodies. “This virus has seen a lot of antibodies,” said Dr Hatziioannou.

Dr Hatziioannou and his colleagues were able to produce advanced mutant proteins in their laboratory that make viruses highly resistant to Covid-19 antibodies. She said Omicron had many mutations in the same regions of the spike protein identified in their own research. “The overlap is quite striking,” she said.

This overlap makes Dr Hatziioannou fear that Omicron may escape some of the antibodies people have acquired from vaccines or Covid-19 infections. Some monoclonal antibody treatments also won’t work against Omicron, she predicted, because the variant’s spike protein is protected from it.

Still, vaccines should provide some protection against Omicron as they stimulate not only antibodies but also immune cells which can attack infected cells, Dr Hatziioannou said. Spike protein mutations do not blunt this immune cell response.

And the booster shots could potentially expand the range of antibodies people make, allowing them to fight newer variants like Omicron. “We’ll see, because these studies are only ongoing now,” she said.

As of yet, there is no evidence that Omicron causes more severe disease than previous variants. And it’s not yet clear how quickly Omicron can spread from person to person.

Some earlier variants, such as Beta and Mu, had developed a strong ability to evade immune defenses. But they never became a serious threat to the world because they proved to be ineffective in transmission.

Certain mutations in Omicron suggest that it may indeed be transmitted well. Three mutations alter a region of the spike protein called the furin cleavage site, which is already known to help the spike protein attach to cells more efficiently.

But Dr Hanage said he was not yet convinced by South African data that Omicron is rampant across the country. “I think it is too early to be final,” he said.

He struggled to see how a variant could sweep across South Africa so quickly, even though the overall rate of new daily infections in the country remains very low. He speculated that the first tests could have been hampered by a technical flaw that could be discovered in the coming days. “I feel like part of the puzzle is missing,” he said.

It might turn out that Omicron’s apparent spread was actually just a coincidence, as has been seen with some previous variants. If a new variant is swept away in a flurry of cases, it will look very contagious when it isn’t.

Even so, Dr Hanage considered a travel lockdown a prudent move that could give governments some time to make plans to deal with Omicron if it lives up to the worst forecasts. Health officials could take advantage of the delay to put in place stricter measures to prevent transmission or boost vaccinations, for example. “But doing it and thinking that it will be enough is not a long term plan,” he said.

Even though Omicron is found to be more transmissible than other variants, Dr Hanage said vaccines would most likely remain vital weapons against him, both slowing its spread and making it more likely that people who get sick will not ‘have a mild Covid-19 instead. to have to go to the hospital.

Omicron is “certainly enough to be taken seriously, but it’s not apocalyptic,” Dr. Hanage said. “It’s not a magic virus. Magic viruses are not a thing.


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