January 6, 2023: The XBB.1.5 omicron subvariant reaching the U.S. is the most contagious type of Covid-19 yet, but it does not appear to make people sicker, the World Health Organization states.

Maria Van Kerkhove, the Covid-19 technical lead of WHO, said that global health officials are worried about how rapidly the subvariant spreads in the northeastern U.S. Several people infected with XBB.1.5 doubles in the U.S. every two weeks, which makes it the most common variant circulating in the area.

“It is the changing subvariant that has been detected yet,” Van Kerkhove told reporters in a press conference in Geneva on Wednesday. “The reason for this is the mutations within this subvariant of omicron permitting this virus to adhere to the cell and replicate easily.”

It has been seen in 29 countries but could be even more widespread, Van Kerkhove states. She said that tracking Covid variants has become difficult as genomic sequencing declines worldwide.

The WHO doesn’t have any information yet on the severity of XBB.1.5, but there’s zero sign at the moment that it makes people sicker than the last versions of omicron, Van Kerkhove added. She stated that the WHO’s advisory group that tracks Covid variants conducts a risk assessment on XBB.1.5 that will be published in the future days.

“The more this virus circulates, the more opportunities it will have to change,” Van Kerkhove stated. “We anticipate further waves of infection worldwide, but that doesn’t have to translate into the high waves of death because our countermeasures keep working.”

Scientists state that XBB.1.5 is regarded as good, dodging antibodies from vaccines and infection as its XBB and XBB.1 relative, two of the most immune evasive subvariants yet. But XBB.1.5 has a mutation that binds it more tightly to cells, giving it a growth advantage.

As XBB.1.5 suddenly spreads in the U.S., China battles an increase in cases and hospitalizations, which abandons its zero-Covid policy in response to social unrest in the previous year. U.S. and global health officials have suggested that Beijing needs to share more data on the increase with the international community.

“We continue to keep asking China for more regular, reliable data on hospitalizations and deaths that are more comprehensive real-time viral sequencing,” WHO Director-General Tedros Adhanom Ghebreyesus stated the reporters in Geneva.