According to data updated by the US Centers for Disease Control and Prevention (CDC) on the 30th, about four of the confirmed cases of new coronary pneumonia in the United States have become Omicron’s new subvariant strain XBB. The confirmed case is XBB.1.5.
Barbara Mahon (Barbara Mahon), director of CDC's Coronavirus & Respiratory Virus Division, said there is currently no indication that XBB.1.5 will cause more severe symptoms than other Omicron variants. In areas with a high proportion of XBB.1.5 cases, such as the Northeast, there has not been a huge increase in hospitalization rates.
According to NBC News statistics, the seven-day average of daily hospitalizations of new crown cases on the 30th reached 42,140, an increase of 4.2% from two weeks ago. It was up more than 9% a week ago.
Mahon pointed out that there are still many unknowns about XBB.1.5, including whether it is more infectious than other Omicron variants. Other scientists worry that XBB.1.5 is better at evading antibodies from vaccines and previous infections with other Omicron variants.
XBB.1.5 is a sub-branch of Omicron variant XBB, and XBB is a recombinant of Omicron sub-variety BA.2.10.1 and BA.2.75.
Together, XBB and XBB.1.5 account for 44% of U.S. cases, more than other Omicron variants.
According to the report of the World Health Organization (WHO), XBB has been found in at least 70 countries so far. In October, it led to a surge in cases in parts of Asia, including India and Singapore.
Laboratory studies have shown that XBB is able to escape antibodies from previous infections or vaccinations, so exposure to this variant makes it more likely to become infected, or reinfected and develop symptoms.
But antibody research is not equal to all situations. There is evidence that other parts of the immune system can protect the body against the virus, and the new crown vaccine should still be effective in preventing severe illness and death.
Rick Bright, former director of the Biomedical Advanced Research and Development Authority (BARDA), took the spread of the XBB variant strain in Singapore as an example. Cases did surge, but the hospitalization rate and death rate did not show a corresponding substantial increase. Bright "We think this is because more people in Singapore have been vaccinated with the latest vaccines and boosters," he said.
Experts agree that the most important thing at present is to inoculate bivalent vaccine booster shots to enhance immunity against newer mutant strains.
