Here’s why one subspecies of SARS-CoV-2 is still dominant:

Electron microscopy images show isolated SARS-CoV-2 particles early in the pandemic. Almost a year after omicron was first detected, scientists say this branch of the coronavirus tree is still thriving.

NIAID/NIH via AP

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NIAID/NIH via AP

Electron microscopy images show isolated SARS-CoV-2 particles early in the pandemic. Almost a year after omicron was first detected, scientists say this branch of the coronavirus tree is still thriving.

NIAID/NIH via AP

During the pandemic, the virus that causes COVID-19 is evolving rapidly, with more and more variants obscuring the world.

However, the World Health Organization has not given the SARS-CoV-2 subspecies a Greek name for almost a year.

Has viral evolution finally started to wane and perhaps become more predictable?

According to dozens of evolutionary biologists, virologists and immunologists interviewed by NPR, the answer is no.

“SARS-CoV-2 continues to evolve very rapidly. Trevor Bedfordis a computational biologist studying viral evolution at the Fred Hutchinson Cancer Center in Seattle. “There is no evidence that evolution is slowing down.”

Instead, the most important evolutionary changes remain restricted to the omicron family, rather than appearing in entirely new subspecies.

Alpha, beta, gamma, and other named variants have sprouted new branches in the SARS-CoV-2 family tree, but their limbs are now omnicorns littered with subvariant stalks. reduced by the branches of the

“The children of Omicron—many direct children and cousins ​​of the diverse Omicron family—supplanted each other,” he said as the dominant strain causing the pandemic. Emma Hodcroft, molecular epidemiologist at the University of Bern. “But that same family has ruled by defeating other lineages.”

One variant to rule them all

Expanding Omicron chicks maintain their dominance through what is known as “Convergence” Evolution — If entities independently develop similar traits due to similar environmental pressures, according to Manon Lagonet Cronwho studies viral genetics at the University of Chicago.

“It looks like the first time we’ve seen evidence of large-scale convergent evolution,” says Ragonnet-Cronin. “We have what people call a swarm of omicron viruses. They have different ancestry within the omicron, but the same set of mutations.”

those mutations These Omicron descendants possess the one power they most need right now. It is the ability to sneak past the immunity people have built through infection, vaccination, or both.

“When you look at evolutionary convergence, that’s the way evolution says, ‘This mutation is really useful, so it’s being selected over and over again,'” he says. Jesse Blooma computational biologist at the Fred Hutchinson Cancer Center in Seattle.

These mutations in the viral spike protein enhance its ability to evade protective antibodies and continue to infect vast numbers of people.

“This virus has won a lot of lotteries, and with these new variants, these new mutations seem like a jackpot.” Jeremy Camilleimmunologist at Louisiana State University.

The Centers for Disease Control and Prevention Currently tracking a dozen omicron subvariantsIncluding BF.7, BQ.1 and BQ.1.1, some of which appear to be among the most immune evasive to date.

Fortunately, the immunity people have built up through vaccination and infection still seems to protect most from serious illness and death.

but newer A highly contagious subvariant of Omicron could help fuel yet another surge.

A family tree still full of surprises?

As dire as this sounds, Omicron’s long-term dominance gives some scientists hope.

In one relatively optimistic scenario, the virus could continue to evolve this way for a long time, drifting in a more subtle evolutionary direction like the flu, without suddenly changing its behavior to become more dangerous.

“Perhaps the fact that we got out of some stage [in the pandemic] Entirely new viruses entering and dominating from different parts of the tree could point to a more stable future for viruses,” Hodcroft said.

But that means more people will still get the virus. Many will still be seriously ill, die, or be left behind by a long COVID, and the virus is still so new that it’s impossible to know how it will evolve in the future, experts say. tells his NPR.

“We are literally dealing with a completely new virus here,” says christian andersen, an immunologist at Scripps Research. “We don’t know how many other routes this particular virus might have. We don’t know at this stage.”

For example, there’s no way to rule out the possibility that dramatically different subspecies will reappear after stewing in the bodies of people with compromised immune systems that can’t get rid of the virus. This allows the virus to interact extensively with the human immune system and even find favorable mutations.

“I assure you that there are people who are persistently infected with Delta and Alpha and have some really weird mutational combinations. Michael Worobey, an evolutionary biologist at the University of Arizona. “And I’m fully prepared for an event like delta-based or alpha-based Omicron. One of the zombie viruses that’s cooking up inside someone emerges.