A new type of coronavirus has resolved, sparking fears of an increase in winter

The spread of BQ.1.1 is a concern because several 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 infection. Even people who have recently received bivalent booster shots from Pfizer or Moderna — which have been updated to accommodate the previously prevalent BA.5 variant — have alarmingly low antibodies to protect against the new virus.

“We can see a lot more COVID in the winter,” said Dr. Daniel Koritzkes, chief of infectious diseases at Brigham and Women’s Hospital. But he noted that people who got the new boosters had more BQ.1.1 antibodies than those who only received the original boosters. “So it’s better than nothing.”

The researchers also warn that BQ.1.1 could pose a greater threat to people who are immunocompromised and those who develop severe infections.. Throughout the pandemic, drugs made with synthetic antibodies have helped prevent or treat infections in people at risk of serious illness. But as the virus has evolved, fewer of these drugs have remained effective.

As a result, the two remaining antibody drugs — bebtelovimab for treating COVID-19 and Evusheld for preventing it — are not expected to work against the new variant.

“If you are so unfortunate as to end up in the hospital with a severe illness, the arsenal that doctors will have to treat is going to be very limited,” said Dr. William Hanage, associate professor of epidemiology at the Harvard T.H. Chan School of Public Health. .

Recently released data from the Massachusetts Department of Public Health shows that COVID-19 cases, hospitalizations and deaths remained relatively unchanged this fall, and in some cases may be slowing. Wastewater data across the state also suggests the virus’s spread has stopped, at least for now.

“There is no sign of a wave or surge of any kind,” said Bronwyn McInnis, director of nurse genome surveillance at the Broad Institute at MIT and Harvard.

The national data is also from the CDC This result reverses, suggesting that newer variants, including BQ.1.1, replace BA.5 without a corresponding increase in infection, Koritzkes said. “It was more of a disruption than a real rebound.” But he and others expect that to change as colder weather and holidays lead to more people congregating indoors.

Dr. Jeremy Luban, a professor and virologist at the UMass Chan School of Medicine, sees indications that BQ.1.1 will be more transmissible. “This means that if you go to a crowded pub, you are more likely to catch the virus than if it was an earlier variant, and to infect more people yourself,” he said.

“It could cause another wave,” Le Pen added, but tempered those unwanted expectations by predicting that things might not be so bad this time. “It is unlikely that this will cause our hospitals to fill the way they used to be,” he said.

Indeed, as we approach the end of the pandemic’s third year, many scientists say immunity to the virus is greater than ever and doubt that new branches of Omicron will cause as many hospitalizations and deaths as their predecessors. Although antibodies against BQ.1.1 may be low, another arm of the immune system made up of T cells can help prevent many mild infections from becoming severe.

“The vast majority of people who have been vaccinated have no particular reason to be concerned about BQ.1.1,” Hanage said.

Pills such as Paxlovid, which block virus replication, are still expected to work against the new variants, whose most worrisome mutations lie in the spike protein used by the virus. cause infection. COVID vaccines trigger the immune system to make antibodies that prevent a spike, but as the virus develops, there are fewer antibodies that still recognize the spike and prevent infection.

Throughout the pandemic, many laboratories have been working to see how well our antibodies can fight off emerging variants. Preliminary results for BQ.1.1, published by several groups this month, are not encouraging.

One study led by Dr. Dan Baruch, director of the Center for Virus and Vaccine Research at Beth Israel Deaconess Medical Center, found that people who had recently received the updated booster vaccine had seven times lower antibody levels to BQ.1.1 than to BA.5. “This suggests that BQ.1.1 will be a challenge for vaccines as well as for natural immunity,” Baruch said.

Two other studies from the Emory Vaccine Center and the University of Texas Branch of Medicine found that BQ.1.1 antibodies were about four to six times lower than BQ.5 antibodies in people who got updated boosters. 1.1 antibodies were lower, and sometimes undetectable, in people who had only one or two doses of the original booster.

“This is concerning,” said Bi Yong Shi, director of the Sealy Institute for Drug Discovery at the University of Texas Medical Branch. He believes his study suggests that the new boosters are better, though he says BQ.1.1 antibody levels are “not very strong.”

Le Pen said that although these antibody studies report similar data, the conclusions scientists draw from them tend toward the glass-half-full-half-empty scenario. While some assert that the new boosters raise antibodies to BQ.1.1, others highlight that these are still fewer than scientists would prefer.

“It’s a good thing that we’re starting to see a broadening of the immune response. But we’re nowhere near where we need to be,” said Mehul Suthar, an associate professor who led one of the studies at the Emory Vaccine Center.

Vaccine makers are reporting the results of their own studies of BQ.1.1 through an optimistic lens. A preliminary version published last week from scientists at Pfizer, BioNTech and Shi Labs showed that the new booster increased antibodies to BQ.1.1 by 4.8-fold, a fact promoted by the company’s statement. The statement did not note that the antibodies were lower than that of the BA.5 variant or the original virus.

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

Antibody immunity from mRNA vaccines made by Pfizer and Moderna is rapidly waning, and with BQ.1.1 antibodies initially low, scientists expect the superinfection to be common.

“It is likely that current vaccines will not provide significant and sustained protection against infection, even with boosters,” Baruch said. “But it is likely that these vaccines will still provide significant protection against severe disease, and that is the most important goal of vaccines.”

As more viruses pass through our waning antibodies, we get sick. Frustratingly, scientists haven’t pinpointed the exact level of antibodies needed to stay healthy. Without this number, called the protection correlation, it is difficult to predict how annoying the new variable will be.

Although Massachusetts is tied for one of the highest per capita vaccination rates in the country, experts warn that a relatively slow uptake of new booster shots could make winters harsher than it needs to be. Only 11.3 percent of people 5 years and older have received the new booster in the United States, according to the Centers for Disease Control and Prevention.

“Your level of immunity to these new variants will be determined primarily by the timing since your last booster or natural infection,” said Dr. Kalpana Gupta, task force leader and chief of infectious diseases at the VA Boston Healthcare System. “And with these newer variants coming out, we really have to get that bivalent booster.”

Ryan Cross can be reached at ryan.cross@globe.com. Follow him on Twitter @tweet.

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