Shanghai detects imported Omicron sublineages but no community infections so far
Omicron sublineages such as the BF.7 and BA.5.2, and the recently emerged BQ.1 and XBB, were found in more than 300 randomly selected viral whole-genome sequences from patients in Shanghai, according to a recent research.
Responding to people's fear of spreading new strains, Yuan Zheng'an, a member of the city's pandemic control expert team, said the BQ.1 and XBB sublineages are only found in imported cases in Shanghai, and there are no community infections so far.
The analysis of the 369 viral genomes from COVID-19 patients at the Shanghai Public Health Clinical Center revealed a certain number of sublineages of the SARS-CoV-2 Omicron family.
Beijing and Guangzhou cases were dominated by BF.7 and BA.5.2, respectively.
By contrast, cases that originated from Hebei Province and Shanghai showed a larger diversity of Omicron sublineages, with Shanghai cases having a more representation of imported BQ.1 and XBB sublineages.
The results came from the research article "Primary assessment of the diversity of Omicron sublineages and the epidemiologic features of the autumn/winter 2022 COVID-19 wave in the Chinese mainland," published on the journal Frontiers of Medicine in late December.
The research team was led by Chen Saijuan, an academician of the Chinese Academy of Engineering, as well as leading medical experts at local hospitals and research institutions.
A total of 353 (95.66 percent) out of the 369 genomes were clustered into four main sublineages: BA.5.2 (172, 46.61 percent), BA.5.3 (118, 31.98 percent), BA.2.75 (36, 9.76 percent) and recombined strains (27, 7.32 percent), according to the research.
XBB.1.5 has been dominant in the United States in the past week, accounting for 40.5 percent of new COVID cases. It almost doubled the level in the week of the Christmas holiday, according to the US Centers for Disease Control and Prevention.
XBB is expected to become the top strain around the world in a short period of time after it has replaced BQ.1 and BQ.1.1, which are offshoots of the BA.5 subvariant, to become the top in the US.
Experts said XBB is worthy of close attention because it is harder to detect and more difficult to stop due to reduced effectiveness of vaccinations or treatments.
Ling Yun, deputy director of the Shanghai Public Health Clinical Center, said patients of imported cases, all of whom should have centralized quarantine at the center, are under strict closed-loop management, and thus the city is yet to see community infections of new Omicron sublineages including BQ.1 and XBB.
