Newer subvariants are ‘most resistant’ to COVID vaccines, antibody drugs, study says

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A look at the latest U.S. government coronavirus data shows several subvariants — all descendants of omicron — in competition with each other when it comes to causing virus cases.

Now four newer subvariants spreading are the “most resistant” to protection offered by both the original COVID-19 vaccines and the updated boosters targeting omicron, according to a new study published Dec. 13 in the journal Cell.

These subvariants, BQ.1, BQ.1.1, XBB and XBB.1, are are also resistant to COVID-19 antibody treatments, the work involving researchers from Columbia University’s Vagelos College of Physicians and Surgeons and the University of Michigan found. The group presents “serious threats” with potential to “fuel” another COVID-19 surge, the scientists warned.

“It is alarming that these newly emerged subvariants could further compromise the efficacy of current COVID-19 vaccines and result in a surge of breakthrough infections, as well as re-infections,” study authors wrote.

In the U.S., BQ.1 and BQ.1.1 are dominating COVID-19 cases and made up about 70% of those reported for the week ending Dec. 17, according to the latest Centers for Disease Control and Prevention data. Meanwhile, XBB made up 7.2% of cases.

While study authors are “especially” concerned over the resistant qualities of XBB and XBB.1, the good news for the U.S. is that XBB.1 — which became predominant in Asian countries including India and Singapore — isn’t recorded as one of the many omicron subvariants causing the country’s recent cases.

For the study, researchers analyzed blood samples from five different groups of vaccinated people.

This was described as a limitation of the work because it was conducted in vitro as blood samples were examined but not the patients themselves. The authors wrote that while in vitro COVID-19 studies have “largely” predicted outcomes in people, it calls for similar clinical studies in people.

The study is peer-reviewed and published as a preproof, meaning it’s not the final version and will go through further copy editing and possible revisions.

Subvariants are ‘barely susceptible’ to protection offered by vaccines and infection

In the research, the patients’ blood samples studied were from:

  • Those who received three or four doses of original mRNA COVID-19 vaccines

  • Those who recently got an updated COVID-19 booster as a fourth dose after getting three original mRNA vaccines

  • Those who had a breakthrough infection caused by omicron BA.4 or BA.4 after getting vaccinated

Overall, the newer subvariants were “barely susceptible” to the neutralizing capabilities of the original and updated COVID-19 vaccines, researchers wrote. They are better at evading virus neutralizing antibodies offered from both vaccination with updated boosters and breakthrough omicron infections.

The updated, “bivalent” COVID-19 vaccines target omicron BA.4 and BA.5, according to the Food and Drug Administration. Currently, the BA.5 subvariant ranks third as the most dominant subvariant spreading in the U.S. and made up 10% of cases for the week ending Dec. 17, the CDC’s data shows.

Despite the threat posed by the four newer subvariants, researchers emphasized that “although infections may now be more likely, COVID-19 vaccines have been shown to remain effective at preventing hospitalization and severe disease even against omicron” and long COVID.

Most people in the U.S. haven’t gotten new boosters as subvariants spread

The study comes as just about 14% of the U.S. has gotten an updated booster dose, according to the CDC.

For many people in the U.S., COVID-19 appears to be of a lesser concern this winter even as public health officials continue advising getting the updated shots, according to the Kaiser Family Foundation.

According to the foundation’s latest COVID-19 Vaccine Monitor, about four in 10 adults surveyed, 38%, said they already got the booster or will get it “as soon as possible.”

In contrast, 12% of adults said they will wait and see, 13% said only if the updated booster is required, and 9% answered they definitely won’t get it, according to the results published Dec. 16.

This latest poll was conducted Nov. 29 through Dec. 8 and included 1,259 people in the U.S.. The margin of error was plus or minus 4 percentage points.

Another study found that older adults may benefit the most from the updated shots as they’re more at risk for severe COVID-19 illness, McClatchy News previously reported.

Newer subvariants resist antibody treatments

Additionally, when it came to monoclonal antibodies, the BQ.1, BQ.1.1, XBB and XBB.1 subvariants were “completely or partially resistant” to those tested, the study found.

When the work was conducted, bebtelovimab was the only remaining monoclonal antibody drug authorized after older COVID-19 subvariants “knocked out” the use of the others, according to the research.

However, the dominance of BQ.1 and BQ.1.1 changed this as bebtelovimab is no longer authorized for emergency use by the FDA as of Nov. 30, according to the agency.

The FDA said the treatment is “not expected to neutralize” those subvariants.

This is consistent with the study, which found both the BQ and XBB subvariants are “completely resistant” to bebtelovimab.

They’re also totally resistant to Evusheld, which is a combination of two monoclonal antibodies for immunocompromised people who are not recommended to get a COVID-19 vaccine or may not have an “adequate” immune response from it, according to the FDA. Evusheld is the “only option for pre-exposure prophylaxis of COVID-19.”

For these people, study authors wrote that “this poses a serious problem.”

“The urgent need to develop active monoclonal antibodies for clinical use is obvious,” researchers said.

Ultimately, the researchers found that the “BQ and XBB subvariants present serious threats to current COVID-19 vaccines, render inactive all authorized antibodies, and may have gained dominance in the population because of their advantage in evading antibodies.”

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