A sub-variant of Omicron, XBB.1.5, is causing concern among scientists after it spread rapidly in the United States in December, according to the Reuters news agency.

Germany’s health minister has expressed concern over a new sub-variant of COVID-19 linked to an increase in hospitalizations in the northeastern US, adding that Berlin is closely monitoring the situation.

While most of the world is watching the rise in the number of COVID cases in China, infectious disease experts are also increasingly concerned about the highly contagious Omicron XBB.1.5, which accounts for more than 40% of cases in the US, according to official figures last week.

Here’s what we know so far:

What is XBB.1.5. and how they behave

The World Health Organization’s chief epidemiologist, Maria Van Kerkhove, said XBB.1.5 is the most transmissible Omicron subvariant identified to date. It spreads rapidly due to the mutations it contains, which allow it to stick to cells and reproduce easily.

“Our concern is how transmitted it is,” Van Kerckhove said during a briefing with reporters on Wednesday.

According to the US Centers for Disease Control and Prevention, XBB and XBB.1.5 accounted for 44.1% of COVID-19 cases in the United States in the week ended Dec. 31, compared with 25.9% the previous week. diseases

According to the WHO, it has also been found in 28 other countries around the world.

XBB.1.5 is another descendant of Omicron, the most infectious variant of the virus that causes COVID-19 and is now dominant worldwide. It is a descendant of the XBB first discovered in October, which in turn is a recombination of two other Omicron sub-variants.

How dangerous is this Omicron sub-variant

The WHO said that they do not yet have data on its severity, nor do they have a clinical picture of its impact. She said she doesn’t see any signs that his severity has changed, but increased transmission is always a concern.

“We expect new waves of infections around the world, but this should not lead to new waves of deaths because our countermeasures continue to work,” Van Kerchow said, referring to vaccines and treatments.

She said the WHO cannot currently link the rise in hospitalizations in the northeastern United States to this option, given that many other respiratory viruses are also circulating.

Virologists agree that the appearance of a new subvariant does not mean that a new crisis has arrived in the pandemic. New variants are expected as the virus continues to spread.

XBB.1.5 is likely to spread globally, but it remains unclear whether this will cause a new wave of infections worldwide. Current vaccines continue to protect against severe symptoms, hospitalization and death, experts say.

There is no reason to believe that XBB.1.5 is of greater concern than other variants that appear and disappear in the ever-changing landscape of COVID-19 mutants,” explained Professor Andrew Pollard, director of the Oxford Vaccine Group.

What does WHO do?

The WHO Technical Advisory Group on Virus Evolution is conducting a risk assessment of the subvariant.

Van Kerchow said on Wednesday that he hoped to publish it in the coming days.

The WHO said it is closely monitoring any possible changes in the severity of the subvariant through laboratory studies and real-world data.

• Read also China’s defiant response after WHO’s accusations of concealing the scale of the COVID-19 pandemic in the country

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