Borders under surveillance, quarantine, tests… Since the appearance of the Covid-19 virus in 2019, the Chinese authorities have imposed strict health restrictions in the country. In November 2022, protests finally caused China to lift its “zero Covid” policy, leading to an explosion in the number of cases. Faced with the latter, several countries, including France, Japan, the United States and Italy, had imposed restrictions on travelers from China at the end of last year.
The international scientific community feared the appearance of new variant strains that were more transmissible or more dangerous. But a study published on Wednesday February 8 finally reveals that there is “no evidence that new variants have emerged” during this period. The study by Chinese researchers analyzed 413 samples from Beijing, sequenced between November 14 and December 20, 2022.
“The virus did not need to mutate”
For Yannick Simonin, virologist at the University of Montpellier and researcher at the National Institute of Health and Medical Research (Inserm), the results of this study “are not really a surprise”. For more than a year, “the majority variants in circulation remain of the Omicron family, even if there are some small differences in the sequencing of these variants”.
With China’s “zero Covid” policy, the circulation of the virus was zero in the country when the restrictions were lifted and the Chinese immune barrier was therefore non-existent. So, “the virus did not need to create new variants to circulate, nor to mutate to be contagious”, explains the virologist.
“Little information from the Chinese authorities”
Nevertheless, Wolfgang Preiser and Tongai Maponga, virologists at the University of Stellenbosch in South Africa, call for caution in the medical journal that publishes the study: “If new variants have emerged during the wave, the study was probably too old to detect them. »
The arrival of a new variant in the coming weeks is therefore not completely ruled out, especially since “we have little information from the Chinese authorities”, recalls Yannick Simonin. And while the latest data shows that the Chinese today have immunity similar to that of Europeans, the latter “has had a considerable cost in terms of death toll and hospitalization. In China, it’s a bit like leaving at the start of the pandemic, while in France our immunity has been built up over time.
According to the researcher at Inserm, the observation of the sequencing carried out for this new study “offers reassuring data and only confirms the latest available”. The new variants that will appear “will have fewer and fewer differences, and the situation will gradually approach that of the flu which comes back every year”, projects Yannick Simonin. The most vulnerable could then – as during the vaccination campaign still in progress and launched in 2022 – be vaccinated at the same time against the flu and against Covid-19.
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