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What to Know: A New COVID-19 Variant Gains Traction

January 03, 2023

Heading into 2023, a new dominant COVID-19 subvariant has emerged in the U.S.

The latest report from the CDC indicates that the XBB.1.5 variant accounts for more than 40 percent of U.S. cases. The Omicron variant had been gaining traction during recent weeks heading into the winter holidays.

“Regarding XBB, experts are watching a subvariant called XBB.1.5 that was detected in New York and has a mutation that has been linked to immune escape,” the Center for Infectious Disease Research & Policy noted. “Scientists suspect that XBB.1.5 has a growth advantage over BQ.1.1.”

Here’s what you need to know:

  • Background:  XBB.1.5 is related to the Omicron XBB variant, which is a recombinant of BA.2.10.1 and BA.2.75 sublineages, the World Health Organization noted (WHO).
  • Characteristics:  Public health leaders are monitoring the subvariant for its immune evasiveness. Early indicators suggested the variant may pose a higher reinfection risk when compared to other Omicron sublineages.
  • Gaining prominence:  XBB.1.5 surpassed the Omicron subvariants BQ.1.1 and BQ.1 as the main circulating variant in the U.S. During the week ending December 24, XBB.1.5 accounted for 21.7 percent of cases before climbing to nearly 41 percent last week.
  • Case counts:  There were more than 402,000 COVID-19 cases reported during the week ending December 28. Infectious disease specialists are following the potential impact of the winter holidays as they track the spread of COVID-19 and other respiratory illnesses.
    • The seven-day average for new hospital admissions for patients with COVID-19 (5,545) remained level compared to the previous week.
  • Quotable:  “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,” the WHO previously noted of the variant and its sublineages.

HAP strongly encourages everyone to stay up to date on their COVID-19 vaccinations and to get a flu shot this winter. Additionally, you can help prevent the spread of respiratory viruses this winter by staying home when sick, washing your hands, and following the CDC’s public health precautions.

HAP continues to monitor the latest COVID-19 public health developments and will provide updates.

The latest CDC variant tracker is available online.