China is stepping up surveillance for Covid-19 variants as an unprecedented wave of coronavirus tears through its population, raising alarm bells around the world and triggering new restrictions on travelers from the country.
In recent days, Chinese researchers and officials have begun uploading genomic sequence data from hundreds of coronavirus samples to Gisaid, a global online database that allows scientists to track mutations in the virus.
The data, although limited, shows that the major Omicron subvariants spreading in China are similar to those previously identified in Europe and North America, where they have been largely supplanted by more virulent strains.
A research team from a major university in Beijing that began submitting sequenced samples from the city said that around 80% of their specimens were the Omicron BF.7 subvariant, while 20% were BA.5.2 . Both are derivatives of the BA.5 strain.
“The sample size is small, so we still need more data to get the full picture,” said a member of the research team who asked not to be named.
The findings are consistent with statements from Chinese health officials who said the two Omicron subvariants are responsible for the majority of cases in the country, as well as other samples uploaded to Gisaid from Fujian, Guangdong, Sichuan and other provinces.
Data from the US Centers for Disease Control and Prevention estimated that the BA.5 subvariant was responsible for 80% of US Covid cases in September, but had fallen to 7% by mid-December . BF.7 was found in 7% of US samples in November and was only 4% the week before December 24.
This month, Xu Wenbo, a senior official at the Chinese Center for Disease Control and Prevention, said the institution was developing a nationwide genetic database of Covid samples.
Xu said three hospitals in each province will take samples from at least 25 Covid patients a week, but it is still unclear whether the system has been put in place. Health officials are struggling to cope with the influx of elderly Covid patients he has Hospitals and emergency departments are overwhelmed.
Beijing’s decision to cut most Covid testing while releasing implausibly low death figures has sparked growing unease that it is again suppressing information to cover the extent of the outbreak, such as when Covid has was first detected in Wuhan.
Last week, top Chinese health officials privately felt the country was see 37mn of new infections per day, with the rate of spread of Covid continuing to increase. Airfinity, a UK-based health data group, has forecast 1.7 million deaths across China by the end of April 2023.
On Wednesday, the United States cited “lack of adequate and transparent data” in revealing Covid testing requirements for air travelers from China.
Japan, India, Taiwan, South Korea and Italy have also imposed restrictions on Chinese arrivals in anticipation of a surge of visitors as the country reopens its borders. Italy found more than half of passengers on a post-Christmas flight from China to Milan were infected, but on Thursday it said no new variants had been found among the sequenced cases.
Gisaid said that over the past week, China has submitted nearly a thousand virus genomes, and China’s CDC provincial offices have “significantly increased the number of submissions of genomic sequences and associated metadata from of samples”.
The head of a Chinese Covid vaccine maker said health officials were very concerned that subvariants such as XBB and BQ, which are prevalent elsewhere, would lead to a second wave of Covid within months. come. Data from Gisaid shows that the strains have started circulating in Shanghai.
“Given the vast outbreak, it’s almost certain that China will eventually have its own variant, we just don’t know how serious or dangerous it will be,” he added.
Ben Cowling, professor of epidemiology at the University of Hong Kong, said it made sense to be wary of new variants emerging in China, but added that “more sequencing would be better of all countries”.
“It’s not fair to say that only China should do more sequencing,” he said.
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