Fast and stealthy new Covid-19 variants poised to accelerate winter growth

Fast and stealthy new Covid-19 variants poised to accelerate winter growth
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A rush of new Covid-19 variants is gaining global traction, raising fears of a winter wave.

In the US, these are BQ.1, BQ.1.1, BF.7, BA.4.6, BA.2.75 and BA.2.75.2. In other countries, the recombinant variant XBB is rising rapidly and is fueling a new wave of cases in Singapore. Cases are also increasing in Europe and Great Britain, where these variants occur.

Dr. Peter Hotez, who directs the Vaccine Development Center at Texas Children’s Hospital, says he thinks of them as variants of Scrabble because they use high-scoring board game letters like Q, X, and B.

As the US moves into autumn, the number of Covid-19 cases is decreasing. Normally, this would be cause for hope that the nation can ride out the waves of the past two pandemic winters. But virus experts fear that with this flurry of new variants, the downward trend could soon reverse.

Taken together, the variants accounted for nearly 1 in 3 new Covid-19 infections nationwide last week. final estimates From the US Centers for Disease Control and Prevention.

Updated bivalent booster vaccines and antiviral drugs such as Paxlovid are expected to continue to protect against the severe consequences of Covid-19 infections caused by new variants.

But the new variants are particularly devastating for millions of Americans with weakened immune systems. New research Changes in these variants make them resistant to the latest lab-generated antibodies available to help treat and prevent severe cases of Covid-19, and the US government is running out of money to encourage the creation of new ones.

It is not known whether this batch of new variants will each continue to run together, sharing a piece of the Covid-19 infection pie, or whether one will rise to overtake the others, as in previous surges.

Although they each descend from slightly different branches of the Omicron family tree, these new shoots have evolved to share many of the same mutations, a phenomenon known as convergent evolution.

Some experts believe that this convergence means we are entering a new stage in the evolution of the virus, which will see several variants circulating at the same time.

“What can happen is that we have several co-circulating, semi-dominant lineages going into the winter season,” said Nathan Grubaugh, associate professor of epidemiology at the Yale School of Public Health.

“This means that with convergent evolution, perhaps several different lineages can independently acquire similar levels of transmission against a single new variant.

“This is what happens for most pathogens, such as influenza and RSV,” Grubaugh wrote in an email. “Now that the virus is so well adapted to human transmission, many of those in circulation have a high degree of fitness.”

Maria Van Kerkhove, the World Health Organization’s technical chief of the Covid-19 response, said on Tuesday that the large mix of new options is making it difficult for the WHO to assess as countries dial back their controls.

“That’s why we have to be ready for it. Countries need to be in a position to implement surveillance, deal with an increase in cases, and possibly deal with an increase in hospitalizations. We do not see any change in intensity yet. Our vaccines remain effective, but we must remain vigilant,” he said.

For now, the Omicron subvariant BA.5 is still number one in the US. According to CDC estimates, it caused about 68% of new infections in the US last week, but it is quickly competing with several new sub-lineages – notably BQ.1 and BQ.1.1.

Each of the BVs accounted for just 6% of new infections in the US last week, but in recent weeks the share of new Covid-19 infections caused by these viruses has doubled every six to seven days – a rapid rate of increase against BA.5 . , is already a very suitable virus, Dr. Anthony Fauci, who heads the National Institute of Allergy and Infectious Diseases.

And these are just two of the new products of the Omicron generation that move.

“The projections vary a little bit, but generally, by mid-November, most people feel they’re going to be at a significant rate, leaving BA.5 behind as the dominant option,” Fauci told CNN.

These variants are different from BA.4 and BA.5, but they are derivatives of those viruses resulting from genetic drift. Thus, they share many parts of their genome with that virus.

Their changes are not on the scale of what happened when the original Omicron arrived on the scene in November 2021. This strain of the long-extinct virus has come out of genetic left field, perplexing researchers and public health officials. catch

This time, Fauci says, we’re as ready as we can be for the last batch of options.

“It’s not that different from BA.5 that it would completely get rid of the protection you would get from a vaccine” — if people were just shot, Fauci said.

The bivalent booster vaccine approved in September protects against the original strain of the coronavirus, as well as the BA.4 and BA.5 subvariants.

“We have the BA.5 bivalent updated vaccine as a booster that we get people to do. It is still compatible with the dominant BA.5 variant and will probably have a fairly good degree of cross-protection against BQ.1.1 and others, but the adoption of these vaccines as we already have them. Mid-October is a disappointment,” he said.

According to the latest CDC data, 14.8 million people received an updated bivalent booster six weeks after the campaign promoting it. That’s less than 10% of the population eligible to buy one.

Poor uptake of new boosters, immune evasion of new variants and weakened population immunity is almost certainly a recipe for increased cases and hospitalizations in the coming weeks.

“It’s probably going to be significantly larger than the BA.5 wave, at least that’s what I expect,” said Mark Zeller, a project scientist at the Scripps Research Institute monitoring options. But Zeller says he doesn’t expect this winter’s surge to reach the height of January’s Omicron wave.

Hotez says that people should not panic over this news, but should be careful.

“We’re underperforming as a nation where people get their two-valued boosters,” Hotez said.

The genetic changes these variants share help them avoid the immunity induced by vaccines and past infections—a recipe for reinfections and breakthrough infections, especially for people who don’t have an updated booster.

Crucially, some options also appear to be impervious to the latest lab-engineered antibodies available to protect against severe Covid-19 infections: an antibody treatment called bebtelovimab, developed by Eli Lilly, and a combination of two long-acting antibodies in Evusheld, developed by AstraZeneca, and used in immunocompromised patients. a shot that helps prevent people from getting sick in the first place.

If these antibodies stop working against the virus, the US will still have Covid-19 antiviral drugs such as paxlovide, molnupiravir and remdesivir to help those at risk of severe complications.

But antibody therapy is especially important for people whose immune function is weakened by drugs, disease, or age. These are people whose bodies do not react strongly to vaccines.

Antibodies are also needed to help people who cannot receive antiviral treatment because of possible reactions with other drugs.

White House Covid-19 Response Coordinator Dr. Ashish Jha says the federal government has pushed development of new monoclonal antibodies during the pandemic, promising new treatments once they are developed.

The government can no longer do this, he said, because Congress has refused to provide additional funding for the Covid-19 response.

As a result, the development of new antibodies and other new therapeutics is lagging behind.

“So even if we had the money today, it would take months to bring a monoclonal to market, and we don’t have the money today anyway,” Jha told CNN.

Jha said this means the nation faces the fall and winter with a smaller arsenal against the virus when it needs to expand its options.

“There isn’t a monoclonal seat ready to go tomorrow that we can just buy off the shelf,” he said.

Antibodies are a losing proposition for companies because they require millions of dollars in investment to develop, and because the virus evolves so quickly, they may only be effective for a few months.

“It’s a terrible business model,” Jha said.

Management is considering ways to commercialize parts of the Covid-19 response — getting out of the business of buying vaccines and treatments — ultimately passing the cost on to consumers and insurers. But Jha says the process must be driven by “needs on the ground and the realities of the virus.”

He says current realities require the government to continue to stimulate the development of new treatments, and he expects the Biden administration to again try to ask Congress for more funding.

“And the truth is, if we want monoclonals to protect high-risk people — which we do — then at this point, given the rate of viral evolution, the U.S. government has to be a major player in that role,” Jha said. “The market cannot deal with this alone.”

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