New COVID Variant of Concern XBB May Lack Surge Potential

Lisa O'Mary

November 28, 2022

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A new coronavirus variant called XBB is marching up the CDC's watchlist and has achieved the label "variant of concern."

Currently accounting for just 3% of cases nationwide, it is somewhat more prevalent in the Northeast, where it accounts for 5% of cases, according to the CDC's variant tracker called Nowcast.

XBB has been on the CDC's radar since earlier this month, when it first began doubling its case counts every 12 days. It is a combination of two Omicron subvariants (BA.2.10.1 and BA.2.75) first seen in September and is among a growing group that could render some antibody treatments ineffective.

Singapore was among Asian countries reporting high case counts of XBB recently. At a White House news briefing last week, Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said he didn't see XBB as a major threat.

"They had [an] increase in cases, but they did not have a [accompanying] major increase in hospitalizations," he said of XBB in Singapore.

A University of Cambridge researcher concurred when speaking to CBS News.

"There has been a rapid rise in XBB, but it doesn't look like it's particularly more severe than other variants," said Derek Smith, PhD, director of the Center for Pathogen Evolution at the University of Cambridge.


CDC: "Nowcast Week Ending 11/26/2022," "CDC/IDSA Clinician Call Nov. 12, 2022."

The White House: "Press Briefing by Press Secretary Karine Jean-Pierre, COVID-⁠19 Response Coordinator Dr. Ashish Jha, and Chief Medial Advisor Dr. Anthony Fauci," Nov. 22, 2022.

CBS News: "XBB variant's arrival won't cause a new deadly COVID surge, officials hope."


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