BEIJING – China has yet to detect any dangerous Covid-19 mutations in the six weeks since the virus was unleashed on the country’s 1.4 billion people, after the abandonment of the rigid curbs that held the pathogen largely at bay.

That is bolstering hope that a new variant after Omicron – one that could set the world back in its attempts to move past the pandemic – is less likely to emerge, even as China contends with an explosive wave of infections.

It is a stark contrast to more than a year ago, the last time the World Health Organisation (WHO) christened a new strain. Back then, concerns were high that the Greek alphabet might be exhausted soon. There is now little room left in some of the virus’ key architecture for any major mutations, according to one of China’s top scientific advisers.

Most of the changes that gave rise to new variants occurred in the spike protein, the portion of the virus used to latch onto healthy cells that works like a key fitting into a lock. The raft of modifications in an important amino acid on the spike protein means it is close to saturation, Dr Zeng Guang, former chief scientist at the Chinese Centre for Disease Control and Prevention, said at a seminar on Thursday, local media Caixin reported.

Future variants

While it is still possible that Omicron could evolve further or undergo changes such as fusing with other coronaviruses, Dr Zeng said he has “cautious optimism” about the risk of future variants.

China has a clear interest in staying officially free of new variants, after years of geopolitical acrimony over how the virus originated. Other scientists are not as sanguine, warning that even small changes could be devastating and that the emergence of mutations has always been random, defying predictions.

“The next variant will come in due course, whether it’s from China or elsewhere, and it may not be from the Omicron family,” said Professor Eric Topol, director of the Scripps Research Translational Institute in La Jolla, California.

Fresh global concerns over novel variants have taken hold in recent weeks, with countries imposing restrictions on Chinese travellers as the virus swamped the world’s most populous country with breathtaking speed. 

The absence of comprehensive information from China makes it “understandable” that other nations are taking steps they believe will protect their populations, WHO director-general Tedros Adhanom Ghebreyesus said two weeks ago, calling for more details so the health agency can undertake a comprehensive risk analysis.

What researchers fear the most is the risk that the pathogen mutates further, diverging from the highly infectious but less virulent forms of Omicron that have dominated the pandemic since it emerged in November 2021. If that occurs, and a new variant that is expected to carry the Greek letter Pi emerges, all bets are off.

“With Omicron, our Covid-19 wards are still mostly empty,” said Dr Alex Sigal, a virologist at the Africa Health Research Institute in Durban. “At least part of that has to do with the variant, and not only a build-up of immunity. With a new variant, you don’t know what will happen.”

‘Unscientific and ungrounded’

To be sure, China, while largely abandoning testing and tracking of cases, has ramped up genetic sequencing efforts. Nearly 1,000 submissions from more than a dozen provinces have been sent to the Gisaid consortium that has been tracking variants since officials started rolling back the zero-Covid approach in late 2022.

All the strains spreading in China closely resemble the variants previously found elsewhere in the world, according to Gisaid data. The findings are consistent with the results of genetic sequencing done on infected airline passengers from China arriving in other countries, Ms Wu Xi, an official with China’s Ministry of Foreign Affairs, told reporters at a briefing in Beijing held by the National Health Commission on Friday.

“There is no new variant nor significant mutations,” she said. “Therefore, some countries’ accusations and speculation against us is absolutely unreasonable, unscientific and ungrounded.”

Still, with former chief scientist Zeng warning that China’s wave will last another two to three months, there is some way to go before the world is out of the woods. BLOOMBERG