China to track Covid-19 mutations through national hospital network
- Participating hospitals will take samples from patients for genome sequencing and analysis as part of move to living with the virus
- China CDC says130 Omicron sub-lineages have been found in the past three months but none cause severe illness or an increase in death rates
Concerns have also been raised about whether it is possible to track any changes as the country battles a surge in cases at the same time as testing requirements have been scaled back.
Mass PCR testing was cancelled in early December and negative test results are no longer required to return to work or enter public places, including hospitals. There is no encouragement for people to get tested.
To keep track of the emergence of new variants, the Chinese Centre for Disease Control and Prevention (China CDC) has established a data gathering network made up of one hospital in each city, and three cities in each province.
Xu Wenbo, director of the China CDC’s National Institute for Viral Disease Control and Prevention, said each hospital is expected to collect samples from 15 patients in the outpatients and emergency room, 10 from patients with severe illnesses, and all fatalities.
Genomic data from the samples will be uploaded to the national database within a week for analysis and sequencing, laying out the distribution of any sub-lineages that may develop across the country, Xu told a press briefing on Tuesday.
“This will allow us to monitor in real time the dynamics of the transmission of Omicron in China and the proportion of its various sub-lineages and new strains with potentially altered biological characteristics, including their clinical manifestations, transmissibility and pathogenicity,” he said.
“This will provide a scientific basis for the development of vaccines and the evaluation of diagnostic tools, including PCR and antigen tests.”
Xu said more than 130 Omicron sub-lineages had been detected in China in the past three months, including several from the BQ.1 and XBB strains which have been circulating in the US, Britain and Singapore, among other countries, since October.
These are known to be highly evasive from immunity built from past infections or vaccination but do not increase disease severity. The World Health Organization (WHO) has said the potential impact of the BQ.1 and XXB sub-lineages “is strongly influenced by the regional immune landscape”.
While BA5.2 and BF.7 remain dominant in China, “BQ.1 and its sub-lineage have been found in 49 cases in nine provinces, while XBB sub-lineages have been found in 11 cases in three provinces”, Xu said.
There had been no increase in the rate of severe cases and no significant increase in the number of deaths as a result of these sub-lineages, he said.
Xu predicts that the spread of new subvariants – including BQ.1 and XBB – will increase over time and mutations will continue. “As long as it circulates in the crowd, when it replicates, it will mutate.”
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But the possibility is low that a highly transmissible variant with a high disease severity will emerge, as none of the 700 Omicron sub-lineages have caused a significant increase in severe cases and death rates, he said.
“We will monitor changes in disease severity, whether the genome mutates,” Xu said.
The WHO’s advice from October remains current, that the BQ.1 and XXB sub-lineages do not “diverge sufficiently from each other, or from other sub-lineages” to be regarded as new variants of the virus.
