In the US, a significant proportion of new CoV infections can be traced back to the XBB.1.5 variant, which was only recently discovered. US health authority CDC estimates that in the week before the turn of the year, XBB.1.5 was behind about 40.5% of all new infections. The variant may be more easily transferable, according to the CDC.
“We’ve been monitoring XBB.1.5 since mid-November and its frequency has roughly doubled every week,” Richard Neher, head of the research group Evolution of Viruses and Bacteria at the Biozentrum of the University of Basel, told dpa. The variant is characterized by the F486P mutation in the spike protein. This is the part of the virus that it uses to attach itself to human cells.
“This mutation may improve binding to the ACE2 receptor in human cells. What exactly this means is unclear,” emphasized Neher. He is not aware of any indications that XBB.1.5 leads to more severe disease progression.