https://www3.nhk.or.jp/news/html/20220227/k10013503091000.html
From an article published on February 27
A group at the Tokyo Medical and Dental University has analyzed the genes of the Omicron variant of the novel coronavirus, and announced the results of their research that the mainstream virus in Japan is a strain called "BA.1.1" of Omicron variant.
73% are "BA.1.1
The survey was conducted by a group led by Hiroaki Takeuchi, an associate professor at Tokyo Medical and Dental University.
The group analyzed the genes of the virus in 40 patients with the virus from December last year to the middle of this month, and found that about 90% of them were Omicron, and 73% of these were BA.1.1.
BA.1.1 is a further mutation of BA.1 and is included in BA.1 in the domestic count, but the World Health Organization (WHO) is monitoring it as one of the Omicron variants along with BA.2, which is feared to be spreading.
Associate Professor Takeuchi said, "In countries such as Denmark where there have been few reports of BA.1.1, the replacement with BA.2 has been rapid, but looking at the situation overseas, the replacement may be slow in countries where BA.1.1 is the mainstream strain. There is a possibility of a prolonged outbreak of the Omicron variant, and it is important to control the shortage of medical institutions," he said.