A view of the sign of Center for Disease Control headquarters, Aug. 6, 2022, in Atlanta.(Nathan Posner/Anadolu Agency/Getty Images)
By Cecelia Smith-Schoenwalder
XBB is also slightly increasing globally, according to the World Health Organization.
The omicron subvariant XBB was responsible for more than 5% of coronavirus infections this week – up from 4% of cases the week prior and nearly 3% the week before that, according to the Centers for Disease Control and Prevention’s weekly variant update.
XBB is a combination of omicron subvariants BA.2.10.1 and BA.2.75. It is growing in prevalence along with BQ.1.1 and BQ.1 as BA.5 declines.
XBB is also slightly increasing globally, according to the World Health Organization. Last week it increased from more than 2% of worldwide cases to nearly 4%, according to WHO’s weekly COVID-19 report.
WHO said in a statement in October that XBB does not appear to be more severe than other omicron subvariants. But it added that there is early evidence that XBB poses a higher reinfection risk compared to the other sublineages.
“Whether the increased immune escape of XBB* is sufficient to drive new infection waves appears to depend on the regional immune landscape as affected by the size and timing of previous Omicron waves, as well as the COVID-19 vaccination coverage,” WHO said in the statement.
Leading infectious disease expert Anthony Fauci last week said that XBB did not lead to a major increase in hospitalizations in Singapore, where it was first found in August.
“One thing we were encouraged with looking at other countries, such as Singapore, which had a big XBB, they had increase in cases, but they did not have a concomitant major increase in hospitalizations,” Fauci said.
But he did add that XBB has an increased ability to escape protection provided by vaccines.
“It doesn’t fall off the map, but it goes down,” Fauci said about protection levels. “So you could expect some protection, but not the optimal protection.”
Meanwhile, COVID-19 transmission in the U.S. is on the rise, according to CDC data. The trend comes after many gathered for the Thanksgiving holiday and more people head indoors as cold weather spreads.
The Biden administration has ramped up its push to get more Americans updated booster shots that target BA.4 and BA.5 as well as the original coronavirus strain in the hopes of staving off a potential fall and winter coronavirus wave.
But uptake of the booster has not been what experts hoped, with less than 13% of eligible Americans getting the shot so far.