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. 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.