CDC tracking rise of new XBB.1.5 COVID variant, already more than 40% of U.S. cases

Funviralpark 2 years ago 0

The Centers for Disease Control and Prevention announced Friday that it was tracking a new variant of the concern called XBB.1.5. XBB.1.5 is estimated to be responsible for 40.5% of new infections nationwide, according to new figures released on Friday.

The rise of XBB.1.5 overtakes its other Omicron variant cousins ​​BQ.1 and BQ.1.1. wave of infection in autumn. Scientists believe its recent growth may have been caused by a key mutation in addition to what was once one of Omicron’s more immune-evading strains.

Dr. Barbara Mahon, director of CDC Proposed Coronaviruses and Other Respiratory Viruses, said: Division, in an interview with CBS News.

Mahon said the agency had not listed XBB.1.5 separately in previous predictions because the strain did not clear the minimum threshold for the underlying sequences the agency collected.

The agency figure of 40.5% is just a guess, Mahon emphasized, and the current probability interval ranges from 22.7% to 61.0%.

The agency estimates that XBB.1.5 has the highest prevalence in the Northeast. Most of his early cases of XBB.1.5 recorded in the global database by early November were sequenced around New York and Massachusetts.

Officials estimate that XBB.1.5 is now responsible for more than 70% of infections in the New Jersey-New England region.

increased hospitalization

The rise in XBB.1.5 comes as COVID-19 hospitalizations have accelerated across the United States in recent weeks. The pace of new enrollments is worse than last summer’s peak in some regions, but still lower than this time last winter.

“At the moment there is no indication that XBB.1.5 is more serious. But it is really good for people to do what we have been saying for quite some time is the best way to protect themselves. I think it’s about time,” Mahon said. .

This month, the Northeast recorded the worst COVID-19 hospitalization rate of any region in the country. New hospitalizations for Americans over the age of 70 are hitting their highest level since early February in New England, according to the CDC.

About 13% of Americans currently live in areas with “high” COVID-19 community levels, and authorities are now recommending masking. Los Angeles, Miami, and New York City currently rank among the largest counties at these levels.

Mahon said the mutation in XBB.1.5 could be part of an increase in which XBB has failed to gain a foothold. But she added that other factors, such as the increased risk caused by respiratory viruses during the winter holiday season, may also be a contributing factor.

Citing the agency’s recommendation to look for the latest COVID booster shots, Mahon took other precautions such as improving ventilation, testing before gatherings, and masking in COVID-prone areas.

“So that advice doesn’t change at all, and this is a really good time to follow that advice,” Mahon said.

Ungroup XBB.1.5 from XBB

The XBB.1.5 strain, a spin-off of an XBB variant, itself a “recombinant” blend of two previous Omicron strains, sparked a wave of infections abroad earlier this year.

Earlier this year, the Biden administration optimistic voice XBB is unlikely to dominate domestic epidemics. South Asian countries such as Singapore reported that this strain appeared to have a lower risk of hospitalization compared to previous variants of Omicron.

After its initial discovery in the United States, XBB accounted for a small proportion of US cases for several weeks, despite an increasing proportion of the variant from arriving international travelers.

Then, last month, the prevalence of XBB began to balloon in CDC estimates. These numbers will be released weekly in the ‘Nowcast’ forecast based on the sequences the agency has collected so far.

Now, according to the CDC, this increase is primarily due to XBB.1.5. After ungrouping XBB.1.5, officials now estimate that all other XBB infections account for just 3% of the country’s cases.

Beyond its parent, XBB.1.5 has an additional change called S486P.chinese scientist reported This mutation appears to have “greatly enhanced” its ability to bind to cells, which may facilitate its spread.

“Like I said, we’ve been following XBB for weeks. It’s been XBB and XBB.1. It hasn’t really taken off. No,” Mahon said.

Vaccine, treatment, test

Before evolving to XBB.1.5, XBB ranked strains with the greatest immune evasion compared to the previous major Omicron strains.the scientist in Japan reported this week that XBB appeared to be the “most potently resistant variant” to antibodies from breakthrough infections in the strains they tested.

Like BQ.1, XBB is resistant to the roster of monoclonal antibody drugs doctors relied on early in the pandemic before being sidelined by new variants.

Data from a team of federally-backed researchers earlier this year showed that the current batch of updated bivalent boosters contains XBB when tested for antibodies in the blood of people who got the updated boosters. We found that Omicron variants appeared to provide “neutralizing activity”. Original vaccine only.

“We expect this bivalent booster to provide protection against XBB.1.5 as well as protection against other Omicron subvariants. And if people haven’t gotten it yet, do this.” It’s a great opportunity to do that,” Mahon said.

However, antibody responses in that study were also poorer for XBB compared to other strains they studied.

“The XBB.1.5 variant appears to be similar to the XBB tested in our study,” Mehul Suthar of Emory University said in an email to CBS News. It enhances the ability to evade antibodies more efficiently.”

In the case of antiviral drugs like Pfizer’s paxlovid, data from another team of scientists in Japan suggest they retain efficacy against XBB.

“So far, XBB.1.5 has not acquired any new mutations in the viral proteins targeted by Paxlovid,” said Peter Halfmann of the University of Wisconsin-Madison. sensitivity should remain unchanged.” He, one of the study’s authors, told CBS News in an email.

And as for the test, the Food and Drug Administration said on its website on Thursday that one home collection kit (DxTerity’s saliva test for the virus) is “significantly less sensitive to variants with XBB mutations.” ” warned that it had been discovered.

“We will update the page as important new information becomes available, such as when FDA’s analysis identifies tests that may affect the performance of known SARS-CoV-2 variants.” Jim McKinney, spokesman for the regulator, said in a statement.

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