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Move over, BA.5. There are some new kids in town and no one is sure yet if we should be worried.
But there is concern that COVID-19 virus subvariants BQ.1 and BQ1.1 will become a major threat in the U.S. and that XBB could alter the COVID picture globally.
At this point, infectious disease experts have only predictions.
A worst-case scenario would be a surge of one or more strains that evade our immune protections just as a predicted fall and winter surge hits the United States.
At the same time, we know a lot more about SARS-CoV-2 than we did when COVID first became a household name. And despite some widespread pandemic fatigue, people know the basics of protection at this point should it be necessary — gulp — to go back to masking, obsessive handwashing, and keeping a safe distance from our neighbors.
The most recent CDC data shows BQ.1 and BQ.1.1 subvariants have grown to about 12% of circulating virus strains in the U.S., doubling in the past week, compared to only 1% a month ago.
"I don't think we should panic, but I am little concerned," says Hannah Newman, MPH. "I would not be surprised to see a surge of infections as we enter respiratory season and in light of the emergence of new subvariants."
"We are already seeing COVID on the rise in some European countries, in part due to these circulating subvariants," adds Newman, director of infection prevention at Lenox Hill Hospital in New York City.
The emergence of BQ.1 and BQ1.1 in the U.S. and XBB globally is not completely unexpected, says Amesh Adalja, MD. "This is a virus that's going to continue to evolve to become more able to infect us, and so these variants should not be surprising."
Better Protection From Bivalent Boosters?
One unanswered question is how well the new bivalent mRNA vaccine boosters could work against these specific subvariants.
"The new booster is a better match to what is circulating than the old booster, but we don't know what that means in real life," says Adalja, senior scholar at the Johns Hopkins Center for Health Security in Baltimore. It's difficult to answer that question because no one is planning to compare the two booster types in a clinical trial.
Newman is more optimistic. "A bit of good news is that the bivalent COVID booster will provide some protection against these strains, and we really just need people to roll up their sleeves and receive it," she says.
The XBB subvariant, currently surging in Singapore, could be a cautionary tale for the U.S., says Eric Topol, MD, founder and director of the Scripps Research Translational Institute in La Jolla, CA, and executive editor of Medscape, WebMD's sister site for medical professionals.
For example, prior to XBB emerging, the COVID reinfection rate in Singapore was 5%. Now it is 17%. "So that means a lot of people who had an infection are going to get hit again," Topol says. Furthermore, Singapore reports 92% of their population is vaccinated and their uptake of boosters is twice the U.S. rate.
"And despite that, they have a very significant wave, which is going to be bigger than anything except the original Omicron," he says.
Fewer Treatment Options
The drug Paxlovid will continue to play an important role in preventing more severe COVID outcomes, Adalja says. This is because "Paxlovid works on a whole different area of the virus, different from these mutations that get around immunity."
In contrast, evidence so far suggests that monoclonal antibody therapies will not be effective against these new subvariants. "The ability to evade monoclonal antibody treatments is a concern for me, because it could leave our most vulnerable open to more severe outcomes," Newman says.
"If strains are able to escape antibody immunity and monoclonal antibodies aren't effective, we can expect to see more severe symptoms in high-risk individuals who would otherwise benefit from these treatments," she says.
In particular, the monoclonal antibody bebtelovimab and the monoclonal combination Evusheld may be less effective against the new subvariants, Adalja says.
Does Recently Infected Mean Protected?
Most people who had COVID-19 within the past 3 to 6 months will likely have antibody levels to protect them, at least against severe disease, Adalja says. That's one reason U.S. officials suggest people wait 3 months to get a booster after infection and Canadian officials recommend 6 months.
"You're certainly going to be protected against severe disease," Adalja adds. "How long you're going to be protected, how immune-evasive these variants are, and the degree to which their immune-evasiveness reaches, that's going to determine if you're susceptible to infection."
After natural immunity wanes, these immune-evasive variants could infect someone again, but they are more likely to experience a mild case, Adalja says.
Newman agrees. "There is a level of natural immunity that is gained with recent infection. However, it wanes over time. Staying up to date with vaccinations and boosters is the most proven and effective way to achieve uniform protection."
What is known is that COVID is likely to be with us for a while, Adalja says. "I was someone who was very forthright about this, that this was never going away. I wasn't thinking this is like a hurricane that is going to leave one day. I thought this is a new normal," he says.
He adds we're making progress on COVID being managed as an outpatient illness.
The Future Is Uncertain
It's difficult to predict exactly what will happen this fall and winter based on current evidence, says Gregory Poland, MD, an internal medicine doctor at Mayo Clinic in Rochester, MN.
Throughout the pandemic, however, what happens in the U.K. and India has consistently signaled what happens in the U.S. And these other countries are experiencing "significant upticks in the subvariants," he says.
"Unfortunately, there is no crystal ball that will predict for sure what a future wave might look like at this moment," Newman says. "It will really depend on whether a variant will outcompete other strains and the prevention measures taken."
She is also concerned about a convergence of COVID and flu over the winter.
Hannah Newman, MPH, director of infection prevention, Lenox Hill Hospital, New York City.
Amesh Adalja, MD, senior scholar, Johns Hopkins Center for Health Security, Baltimore.
Eric Topol, MD, founder and director, Scripps Research Translational Institute, La Jolla, CA, executive editor, Medscape.
Gregory Poland, MD, internal medicine doctor, Mayo Clinic, Rochester, MN.
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Cite this: New COVID Subvariants Rising: How Concerned Should We Be? - Medscape - Oct 18, 2022.