Covid-19 is ripping through China. Could a new variant of concern emerge?
- Some health experts believe a more severe variant is unlikely to appear, but say it’s critical to closely monitor the situation
- There could be ‘less pressure for the virus to evolve to evade immunity’ in the country after it stuck to strict pandemic curbs for so long
But despite China’s low immunity and 1.4 billion population, some health experts believe a more severe version of the virus is unlikely to appear – though they say it is critical to stay vigilant and closely monitor the situation.
When Sars-CoV-2, the coronavirus that causes Covid-19, replicates during an infection it sometimes changes, and when there are one or more of these mutations it becomes a variant of the original virus. The World Health Organization notes that “the more viruses circulate, the more they may change”.
According to Chen Xi, a global health expert at Yale University, the major Covid-19 outbreak that is ripping through China could have unpredictable effects on the virus.
“The world’s most populous country has a large immunity trap and includes a large number of immunocompromised population, who can harbour the virus for months – that may produce variants of concern,” Chen said.
But he said the risk of new variants emerging from the outbreak could be “a bit less than it seems”.
China had stuck with its zero-Covid strategy for so long that people’s immune systems remained trained almost exclusively on the original versions of the coronavirus, he said, making it easier for the currently circulating strains to spread.
“It’s possible that there will be less pressure for the virus to evolve to evade immunity further,” Chen added.
Stuart Turville, a virologist at the University of New South Wales’ Kirby Institute in Australia, said a variant had yet to create significant concern over increased disease severity in the vaccine era.
“Could a variant appear in China with greater disease severity? As with other countries, it is still possible and needs monitoring carefully,” Turville said.
“Will China end up having their own variant? We simply do not know and it could either be spread over time of variants we see globally and/or potentially something unique. At this point, it looks more like the former with the [Omicron] variant BF.7.”
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However Jin Dongyan, a virologist with the University of Hong Kong, said the general trend was that Omicron was becoming less severe.
“Three-quarters of the world have had large-scale outbreaks and no new variants have appeared, so why would new variants emerge in China?” Jin said, adding that even if there were new mutations, they would not necessarily be more deadly.
“Beijing has reached a peak in Covid-19 infections – have you seen a new variant?”
Health authorities in the eastern province of Zhejiang – home to 65 million people – on Sunday said daily infections had surpassed 1 million and were expected to peak around New Year’s Day at around 2 million daily cases. Yu Xinle, deputy chief of the province’s health commission, told reporters the peak would last for a week.
In Qingdao – a city in the eastern province of Shandong with a population of 9 million – daily infections were at about 500,000, health chief Bo Tao said on Friday. He said they were expected to rise by 10 per cent over the weekend.
While authorities have not released numbers for Beijing, a study by researchers at the University of Hong Kong posted on preprint server medRxiv, suggested the infection peak was reached on December 10.
Experts say detecting and monitoring variants of the virus remains critical.
“While the general evolutionary trend of Sars-CoV-2 is towards milder, more transmissible new variants, we should remain vigilant,” Chen from Yale said, adding it was important to collect “nationally representative viral samples in gene sequencing on a regular basis”.
Chinese health authorities are closely watching the Omicron subvariants that are circulating, Xu Wenbo, head of the National Institute for Viral Disease Control and Prevention under the Chinese Centre for Disease Control and Prevention, said last week.
He said the institute required three city hospitals in every province to carry out genetic sequencing on 15 emergency cases, 10 severe cases and all deaths every week. A national sequencing database for Covid-19 has been set up based on the data from hospitals.
“It will allow us to monitor in real time how Omicron subvariants are circulating in China and the composition of its various subtypes, as well as new variants with potentially altered biological properties,” Xu said. “It will provide a scientific basis for the development of vaccines and the evaluation of diagnostic reagents.”
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But Xu said it was unlikely that a new variant with high transmissibility and greater disease severity would emerge in China.
“Omicron has 709 sublineages and we haven’t seen an increase in severe illness and deaths in its 700 sublineages,” he said. “The general mutation trend of variants is that they are less likely to have increased disease severity.”
