The latest COVID-19 variant to sweep across the country, XBB.1.5, doesn’t appear to cause more serious disease than its predecessors, experts say.
But it appears to be about five times more contagious than an earlier omicron variant, which was five times more contagious than the original virus, said Mehul Suthar, who studies emerging viral infections at the Emory University School of Medicine in Atlanta. “The numbers start adding up.”
As of Dec. 31, XBB.1.5 accounted for more than 40% of cases in the United States, up from about 1% less than a month earlier, according to the Centers for Disease Control and Prevention.
Still, vaccines remain effective at preventing severe disease and death and the antiviral Paxlovid, given in the first few days after infection, “dramatically reduces progression to hospitalization,” said Dr. Daniel Griffin, an infectious disease specialist at Northwell Health in New York.
“We’re not back in the dark days of early 2020,” he said.
Get weekly coronavirus updates in your inbox: Sign up for our newsletter now.
COVID vaccines and new variant XB.1.5: What to know
The primary concern with any new variant is whether vaccines and treatments will remain effective.
“The vaccines are holding. That’s good,” said Dr. Jeremy Luban, an expert on viruses at the University of Massachusetts Chan Medical School.
But “anytime you have a new creature that spreads like this, person to person so rapidly, it puts a big stress on our infrastructure – medical facilities and personnel who are chronically short-staffed. That’s a problem for everybody,” he said.
Suthar led a study, published in December, showing that COVID-19 booster shots, designed to target two different variants, still provide protection against this new one – and better protection than a vaccine directed at just the original virus. “I think we’re heading in the right direction,” he said.
Unfortunately, as has been true for at least the last year with omicron and its subvariants – including this one – the vaccines aren’t as good at preventing infection and mild disease.
And the medical definition of “mild” may not match the average person’s, Griffith said. “People are still pretty miserable,” he said, adding that several patients have complained that a recent infection was worse than a previous one or worse than they’ve felt from nearly anything else in their life.
Why is XBB.1.5 spreading so quickly?
The new variant is spreading fast, Luban said, for one of three reasons or – more likely – a combination:
- Recent holiday gatherings and travel exposed more people and few are wearing masks.
- This variant may be better at transmitting from person-to-person. It appears to bind even more tightly than earlier variants to the body’s ACE-2 receptors.
- It seems to be more resistant than earlier variants to the immune system’s antibodies.
In New York, XBB.1.5 is the vast majority of COVID cases
In the northeast, particularly New York, XBB.1.5 now accounts for the vast majority of COVID-19 infections, Griffin said.
At Northwell Health – which serves New York City, Westchester and Long Island – hospitalizations for COVID-19 are rising, but still just half the level of this time last year. As of Tuesday, there were 783 patients hospitalized at Northwell with COVID, with 10% in intensive care, up from 545 cases a month ago and 467 cases as of Nov. 3.
Why new variants pose a threat
As of early December, XBB and its subvariant made up fewer than 5% of cases, while variants BQ.1 and BQ.1.1 accounted for more than 60%. They now make up about 45%.
The big concern is that a future variant might be more dangerous, Luban said.
“Anytime the virus spreads so fast and replicates so much … could it change in some way that will affect the pandemic? We can’t predict those things,” he said.
CASES EXPLOSE IN CHINA:What that could mean for the United States
And even now, while vaccines and antivirals still work against them, monoclonal antibodies do not. Monoclonals were helpful earlier in the pandemic at preventing high-risk people from ending up in the hospital or even getting infected at all.
“People whose immune system needs help, they’re just out of luck (now),” Luban said.
Luban and the others remain concerned about the ongoing spread of COVID-19 in China. On Dec. 1, China relaxed its long-held “zero COVID” policy, and cases are believed to be exploding there, though the government has not released detailed information.
LATEST:US will require COVID-19 testing for travelers from China
Why you should still avoid getting infected
There’s no doubt that it’s safer to avoid getting infected at all, the experts said. Suthar, Griffin and Lubansupport vaccination with at least three doses and all three said they still mask when in public, indoor spaces.
“The ‘it’s OK if I get infected’ attitude is not the most viable,” Suthar said.
Every infection, even after vaccination or a previous infection, increases the risk for long COVID – potentially debilitating symptoms that can linger for months or longer.
Dig Deeper
Contact Karen Weintraub at kweintraub@usatoday.com.
Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.
