The new, more fit descendant of Omicron Edition begins running its own coronavirus waves

Cases are rising in most states and have increased by more than 50% over the past week in Washington, Mississippi, Georgia, Maine, Hawaii, South Dakota, Nevada and Montana. In New York, more than a quarter of the state’s population is in “high” COVID-19 community-level counties where the US Centers for Disease Control and Prevention recommends indoor masking.

Average daily hospitalizations have increased by about 10% since last week, according to data collected by the US Department of Health and Human Services.

The culprit this time appears to be a spinoff of Omicron’s BA.2 subvariant called BA.2.12.1, which was first flagged by New York state health officials in April.

BA.2.12.1, which is growing about 25% faster than its parent virus, BA.2, accounts for about 37% of all COVID-19 cases across the US, according to new CDC estimates.

BA.2 caused an estimated 62% of all Covid-19 cases last week, down from 70% a week ago.

US, South Africa increasingly struggle with new variants

BA.2.12.1 isn’t the only Omicron branch scientists are looking at.

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After weeks of decline, South Africa saw a rapid increase in its COVID-19 cases over the past two weeks. Test positivity and hospitalizations have also emerged as scientists look at two relatively new subvariants, BA.4 and BA.5, that dominate transmission in that country. According to South Africa’s National Institute of Communicable Diseases, they together account for about 60% of all new COVID-19 cases by the end of April.

These new Omicron subvariants are spreading around the world. According to the website, BA.4 sequences have been reported in 15 countries and 10 US states, while BA.5 is selected in 13 countries and five US states, maintained by a coalition of academic research centers. has gone. Supported by funding from the National Institutes of Health.

Like BA.2.12.1, BA.4 and BA.5 have growth advantage over BA.2.

Omicron subvariants escape immunity

A new preprint study, published ahead of peer review, is pointing to why BA.4 and BA.5 are on the rise: they may have escaped antibodies produced by previous infections previously caused by the Omicron virus, BA.1, Which is the version responsible for this. Huge wave of infections in many countries in December and January. They can also evade antibodies in people who have been vaccinated and have had BA.1 infection, although this is somewhat less common than in people who have only been infected.
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Researchers in South Africa tested the ability of antibodies in the blood to neutralize BA.4 and BA.5 viruses in a laboratory. People who had not been vaccinated but had recently recovered from BA.1 infection saw a more than sevenfold drop in the ability of their antibodies to neutralize BA.4 and BA.5 viruses. In people who had been vaccinated but had recently had a successful infection due to BA.1, the drops were smaller, about three times fewer.

By comparison, the World Health Organization uses an eightfold drop in neutrality as the extent of the loss of protection that requires updating of seasonal influenza vaccines.

The results of the study prompted the researchers to write that “BA.4 and BA.5 have the potential to result in a new infection wave,” making COVID-19 vaccination and booster shots critical to preventing the next wave. .

“From this we conclude, first of all, that Omicron is not a great vaccine in itself, is it?” Alex Sigal, a virologist at the Africa Health Research Institute who led the study, said. “Just because you were infected doesn’t mean you have much protection from further incidents.”

Dr. Eric Topol, a cardiologist, founder and director of the Scripps Research Translational Institute, praised the research, saying that this laboratory was also the first to characterize the first Omicron version: “They have been first-class in all areas of the pandemic. way through.”

He said that overall, the finding was not good news. Even people who have recovered from a COVID-19 infection as recently as December or January can be reinfected by these new subtypes.

“The decline of immune evasion or immune evasion was pronounced in those people,” Topol said, adding that only 1 in 3 people in South Africa have been vaccinated against COVID-19.

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For people who have been vaccinated, “they are not as bad, but they also suffer BA.4 and BA.5 with a less solid neutralizing antibody response,” he said. “Mutations in BA.4 and BA.5 are proving to be a challenge to our immune response.”

Only a few dozen sequences of these viruses have been reported in the US and Canada. Researchers say it is too early to know whether BA.4 or BA.5 will fly in the United States.

It wouldn’t be surprising if they did, said Andy Pecos, a virologist and professor of molecular microbiology and immunology at Johns Hopkins University.

“We’ve seen it over and over again. As one type takes effect in another country, eventually ends up here in the US.” And spreading globally,” Pecoz said.

In the meantime, Topol said, we have our own sub-line to deal with this: BA.2.12.1.

“It can simulate the problems of BA.4 and BA.5,” Topol said. “We don’t know yet because there haven’t been any studies like this from the Sigal lab.”

shared mutation

The BA.4 and BA.5 viruses and BA.2.12.1 have mutations in their genomes at position 452. This region codes for a part of the virus receptor binding domain – the part of the virus that docks at a door outside our cells. The delta variant and a few others carry mutations in this locus. Researchers believe the changes there help the virus bind more tightly to our cells and hide from frontline immune defenders called antibodies that try to stop the virus from invading our cells. .

“It might even lead to better communication between our cells,” Sigal said.

There are also changes in BA.4 and BA.5 at position 486, which is a bit of a head-scratcher because the previous viruses that converged at this location did not do well. They stopped.

“All of a sudden, this guy manages it. So we don’t know what he does,” Siegel said. “I suspect it’s a heavy escape mutation,” meaning it helps the virus hide from our immune system.

Scientists have begun work to try to better understand BA.2.12.1, which has been found in 22 countries, although most sequences have come from the United States.

Pekosz said that he is in BA.2.12.1. increasing copies of He has sent samples of the virus to other research groups to study in his lab and more recently. He said scientists are just beginning to talk about the experiments they want to do to answer two key questions: how quickly it is replicating itself, and how well it evades our immunity. ?

Before the SARS-CoV-2 virus, scientists thought the coronavirus had not changed much. Pekosz said that, looking back, we didn’t know what we didn’t know.

As long as the virus continues to find hosts to infect, it will continue to evolve.

“This virus has shown that it mutates slowly, but when it started to take on good mutations, they just kept coming and coming,” he said.



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