The World Health Organization(WHO) announced Wednesday that XBB—the most likely immune-evading variant of COVID to date—has been identified in 26 countries.
The organization did not name the countries where it found XBB. Levels of this variant increased this month in Singapore, despite a widely vaccinated and increased population, and in Bangladesh. But according to GISAID, an international research organization that tracks changes in the COVID and flu viruses, other countries are also seeing an increase in cases, including Canada, England, and India.
GISAID data shows the highest concentration of XBB or spin-off variants in the past 30 days in Singapore, followed by India, Bangladesh, the USA, Australia, and Denmark. The XBB is a combination of two different Omicron strains. It competes with Omicron’s spawned BQ.1.1 for the title of the most immune-hostile variant to date, surpassing the common ancestor BA.5, which was spread globally this summer. But the WHO report cited “laboratory-based evidence” that XBB is indeed the most antibody-evading variant to date.
While XBB appears to spread more efficiently than other Omicron variants, it remains to be seen whether it causes more severe disease than other strains, the report added.
Emerging Threats
XBBs have not yet been identified in the United States. But its spin-offs-XBB.1, XBB.2 and XBB.3-have, according to GISAID data.
XBB.1 was first identified in the United States on September 15 and accounted for 0.26% of the cases genetically sequenced in the past 15 days, Raj Rajnarayanan, associate professor of research and research at the New York Institute of Technology campus in Jonesboro, Ark, told sources on Monday, referring to GISAID data.
Most of the XBB strains were found in New York State. The WHO said this week that there are almost three times more cases of XBB.1 than XBB worldwide.
It is currently unclear what advantages XBB’s successors, like XBB.1, might have over their parent variant. Compared to XBB, XBB.1 has only “one small change” in the peak light that the virus uses to attach to and infect cells. Rajnarayanan said the impact of the change is unknown.
XBB additionally circumvents the immunity of BQ.1.1 antibodies to the competitor, rendering monoclonal antibody therapies useless in high-risk COVID patients. Both bebtelovimab, the newest monoclonal antibody drug that works against all variants, and Evusheld, which works against some, evade immunity, according to a study last month by China’s Peking University Biomedical Pioneering Innovation Center.
The authors wrote that both can cause more severe symptoms. The authors added that the ability of XBB to evade immunity is “extreme” and approaches the level of immune evasion demonstrated by SARS, the coronavirus that infected thousands of people and caused nearly 800 deaths in the early 2000s.
Scientists, including leading US infectious disease expert Dr. Anthony Fauci, predict that the number of cases will rise in the fall and winter, beginning this month and peaking in January. It remains unclear which variant of COVID may be fueling this wave. But XBB and BQ.1 are the best contenders, experts say.
Source: Fortune
