A new coronavirus variant has taken over, sparking concerns of a winter surge - The Boston Globe

The spread of BQ.1.1 is of concern because multiple small studies published earlier this month suggest the variant is among the best yet at evading antibody immunity, the body’s first line of defense against infections.

Even people who recently received new bivalent booster shots from Pfizer or Moderna — which were updated to match the formerly dominant BA.5 variant — have alarmingly low antibodies to protect against the new virus.

But he notes that people who got the new boosters had more antibodies to BQ.1.1 than those who only received the original boosters.

Researchers also caution that BQ.1.1 could pose a greater threat to immunocompromised people and those who develop severe infections.

National data from the CDC also reflect that finding, suggesting that newer variants, including BQ.1.1, are displacing BA.5 without a corresponding increase in infections, Kuritzkes said.

“That means if you go into a crowded bar, you’re more likely to come out with the virus than if it were a previous variant, and infect more people yourself,” he said.

Even though antibodies against BQ.1.1 may be low, another arm of the immune system composed of T cells can still help prevent many mild infections from becoming severe ones.

Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, found that people who recently received the updated booster shot had about sevenfold lower antibody levels to BQ.1.1 compared with BA.5.

“That suggests BQ.1.1 will be a challenge for vaccines as well as for natural immunity,” Barouch said.

Two other studies from the Emory Vaccine Center and the University of Texas Medical Branch found that BQ.1.1 antibodies were about four to six times lower than BA.5 antibodies in people who got updated boosters.

BQ.1.1 antibodies were even lower and sometimes undetectable in people with just one or two shots of the original booster.

He believes his study suggests the new boosters are better, even though he says the BQ.1.1 antibody levels are “not very robust.”.

Luban said that although these antibody studies report similar data, the conclusions that scientists are drawing from them lean toward a glass half-full or half-empty scenario.

While some emphasize the new boosters raise antibodies to BQ.1.1, others highlight those antibodies are still lower than scientists prefer, he said.

The statement didn’t note that the antibodies were still lower to that variant than BA.5 or to the original virus.

Cambridge-based Moderna said in a statement its new booster spurred a “robust” antibody response against BQ.1.1 without providing data.

Antibody immunity from the mRNA vaccines made by Pfizer and Moderna wanes quickly, and with BQ.1.1 antibodies low to begin with, scientists anticipate that breakthrough infections may be common.