Much of the recent hubbub arose because the US Centers for Disease Control updated its estimates of circulating variants, noting that two— BQ.1 and BQ.1.1, both descendants of the familiar BA.5—combined now account for about 11% of infections in the US. That’s up from less than 1% a month ago. Meanwhile, a variant called XBB has been making inroads in Asia.
The reason for the panicked headlines is that these new Omicron family members are capable of ‘immune escape’—a phrase that sounds scary when taken out of context. It makes it sound as if the virus has evolved past our currently available tools. In reality, it means the virus has mutated in a way that allows it to get around some of the front lines of our immune defence system, our neutralizing antibodies. The world has paid a lot of attention to neutralizing antibodies over the past two years because they are easy to measure, and thus became a proxy for vaccine effectiveness.
But our immune response is far more nuanced than neutralizing antibodies alone, particularly given how much of the population has been both vaccinated and infected with some earlier form of omicron, says Jeremy Kamil, virologist and professor of microbiology and immunology at Louisiana State University Health Shreveport. Vaccinated and previously infected people have other robust and still-intact lines of defence, such as memory T-cells and B-cells. People previously infected also have additional immune cells that reside in the respiratory tract.
“I’m not a fan of that word ‘escape.’ I think a better word is ‘erosion’," says Katelyn Jetelina, author of the US newsletter Your Local Epidemiologist. “This isn’t a binary that the vaccines will work or not work. In reality, it’s a spectrum of effectiveness."
In the end, all of this means that the new variants popping up might mean we see more virus transmission—and more infections. But the shots still do a good job of keeping people safe from severe infection, hospitalization and death. This important message could get lost in the mix of panicked headlines about new variants. That’s particularly dangerous when enthusiasm for covid shots is so low—as of last week, only 14.8 million people in the US had received the updated bivalent shot. That’s less than 7% of the more than 226 million Americans who are eligible for booster doses right now.
The other piece of the story that is too often overlooked is that these new Omicron variants can still be combatted with Pfizer’s antiviral Paxlovid. The drug targets a part of the virus that has remained fairly steady even as the virus has changed, and is shown to be effective at preventing serious cases of the disease—particularly in unvaccinated and older populations.
However, there is one reason to be concerned about BQ1, BQ1.1 and XBB. These new variants threaten to disarm the last two effective monoclonal antibody therapies, AstraZeneca’s Evusheld (used to prevent infection) and Lilly’s bebtelovimab (used to treat infections). The drugs have been important tools to protect immunocompromised people and others at high risk of serious disease. Companies are working on updated antibodies and the US Food and Drug Administration must continue to speed them through emergency use authorizations; and Congress could ensure companies continue to be incentivized to keep developing and manufacturing these drugs by allocating more covid funding.
So, when do we worry? Those alarmist headlines might be justified if an entirely new branch in the Sars-CoV-2 family tree emerges—one that pairs the deadliness of Delta or Beta variants with the transmissibility of Omicron. That’s not nearly as likely as a scenario where more Omicron-like variants continue to emerge, but given the twists and turns this virus has taken, “We have to remain humble," Jetelina says.
And in the meantime, Kamil says that if you are someone who has not had either covid or a booster jab in the past six months, now would be a good time to go get one. Based on what other countries are already seeing, a winter wave driven by one or several of these variants is likely to materialize. But that will only result in another wave of deaths if we stop trusting our still-good defences.
Lisa Jarvis is a Bloomberg Opinion columnist covering biotech, health care and the pharmaceutical industry.
