Giuseppe Michieli''According to data from the Global Initiative for Sharing Influenza Data (#GISAID), as of December 31, 2022, #XBB15 has been detected in at least 74 #countries and regions around the world. The #XBB substrain has also been introduced into #China'', SINA: https://news.sina.com.cn/s/2023-01-03/doc-imxywnct5913193.shtml
''It is worth noting that #XBB is not a virus mutation, but a #recombinant strain of two #BA2 lineages, #BA2101 and #BA275. In contrast, the previous major epidemic strains in the United States, BQ.1 and BQ.1.1, both evolved from BA.5.''