XBB.4 is a sub-strain of XBB. XBB.4 obtained a key mutation on the basis of XBB, while XBB.4.1 obtained a T470N mutation on the basis of XBB.4. Although this strain is not reported in the United States at present, it is suspected that it was introduced into the United States a few days ago according to our data.
CH.1.1 is BM.4' s virus with four consecutive key mutations, BM.4 is a sub-virus of Ba.2.75.3, and XBB virus is a recombination of BM.1.1.1 and BJ.1 It is hoped that the infected person who has been confirmed as CH.1.1 virus by sequencing will inform the surrounding people to participate in sequencing and reporting cases in time.