Published: 12:57, December 31, 2022 | Updated: 13:00, December 31, 2022
Omicron subvariant XBB.1.5 behind 40% of US COVID cases
By Xinhua

A 3D-printed coronavirus model is seen in front of a US flag on display in this illustration taken March 25, 2020. (DADO RUVIC / ILLUSTRATION / REUTERS)

Over 40 percent of COVID-19 cases in the United States are now caused by the highly contagious Omicron XBB.1.5, data from the US Centers for Disease Control and Prevention showed on Friday, with the subvariant doubling from the previous week.

Infectious disease experts have been increasingly worried about the XBB.1.5 variant.

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Every previous two winters, we have seen a surge of infections that peaked in mid-January... and I expect the same to happen this year.

John Moore, Professor, Weill Cornell Medical College, New York

"Ironically, probably the worst variant that the world is facing right now is actually XBB," said Dr Michael Osterholm, an infectious disease expert at the University of Minnesota, in a recent interview with Reuters.

Osterholm added that seven of the 10 US states where cases and hospitalizations are rising are in the Northeast, concurrent with an increase of XBB cases there, he said.

Recombinants of the BA.2 variant, XBB and XBB.1.5, together accounted for 44.1 percent of the total cases in the country for the week ended Dec 31. For the week ended Dec 24, XBB.1.5 had made up 21.7 percent of the total cases.

"Every previous two winters, we have seen a surge of infections that peaked in mid-January... and I expect the same to happen this year," said John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York.

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He added that the difference between last two years and this year is that there has not been a significant increase in the death rates.

The XBB variant has been driving up cases in parts of Asia, including Singapore. It accounted for 3.6 percent of the total cases in the US this week compared with 4.2 percent in the previous week. The agency began reporting data for the two subvariants separately from this week.