An explosion of Covid-19 cases in China, at a time when the country is lifting its "zero Covid" measures , could create a potential breeding ground for the emergence of new variants, health experts warn.
On January 8, China will cease mandatory quarantines upon arrival in the country, the last bastion of its policy of strict restrictions that has kept the country largely closed to the world since the start of the pandemic .
While the government has stopped publishing the number of daily cases, officials in several cities estimate that hundreds of thousands of people have recently been infected, while hospitals and crematoriums are overwhelmed across the country.
With the virus now circulating freely in China, home to nearly a fifth of the world's population, several countries and experts fear that China could become fertile ground for the emergence of new variants . This is especially concerning given the low vaccination rates in the Chinese population .
"Favorable conditions"
Each new infection increases the chances that the virus will mutate, according to Antoine Flahault, director of the Institute of Global Health at the University of Geneva. "The fact that 1.4 billion people are suddenly exposed to SARS-CoV-2 obviously creates conditions conducive to the emergence of variants ," he told AFP.
Bruno Lina , professor of virology at the University of Lyon, France, told the newspaper La Croix: "given the intense circulation of the virus, and therefore the increased risk of mutations, a potential breeding ground for viruses could emerge from China . "
Soumya Swaminathan , who served as chief scientist at the World Health Organization (WHO) until November, also indicated that a large portion of the Chinese population was vulnerable, partly because many elderly people had not been vaccinated. "We need to closely monitor any emergence of variants of concern ," she told the Indian Express website .
Border controls
In response to the surge in cases, the United States , Italy , Japan , India and Malaysia announced this week that they would strengthen their border controls .
Washington will require a negative Covid test starting January 5 for all travelers arriving by plane from China. India and Japan will impose mandatory PCR tests on all passengers arriving from China, a measure that, according to Antoine Flahault , could be a way to circumvent any delays in information coming from Beijing.
The French government, which maintains it is "monitoring the situation very closely ," declared itself "ready" on Wednesday "to consider all necessary measures ." Interviewed on France Inter radio on Thursday, Brigitte Autran , president of the Committee for Monitoring and Anticipating Health Risks (Covars), said she expected a decision "by the end of the week . "
"Border screening has never prevented the virus from entering" and "the only potential benefit" of systematic screening of travelers landing from China would be "to analyze what type of variant" they are carrying, she added.
Sequencing
"If we succeed in sampling and sequencing all the viruses identified in all travelers from China, we will know almost immediately if new variants are emerging and spreading " in the country, explained Antoine Flahault.
Xu Wenbo , head of the virus control institute at the Chinese Center for Disease Control and Prevention, assured that hospitals across the country would collect samples from patients and upload sequencing information to a new national database, enabling authorities to monitor new strains in real time.
More than 130 new sub-lineages of the Omicron variant have been detected in China in the past three months, he said last week.
Among them are XXB and BQ.1 and their own sub-lineages, which have spread to the United States and parts of Europe in recent months as a swarm of sub-variants vied for dominance worldwide.
New waves
However, BA.5.2 and BF.7 remain the main Omicron strains detected in China, Xu Wenbo said, adding that the different sub-lineages will likely co-circulate.
"A soup" of more than 500 new sub-variants of Omicron has been identified in recent months, recalled Antoine Flahault.
"All variants, when they are more transmissible than the previously dominant variants - such as BQ.1, B2.75.2, XBB, CH.1 or BF.7 - definitely represent threats, as they can cause new waves ," the epidemiologist said.
"Currently, none of these variants appear to present any new particular risks of more severe symptoms, but this could be the case for new variants in the near future ," he added.
