HONG KONG — Analysis of Covid-19 cases in Beijing suggests no new variants have emerged from the recent outbreak in China, according to a study published Wednesday.
Faced with rare mass unrest after nearly three years of strict “zero Covid” policies, the Chinese government dropped most of its restrictions on Dec. 7. The sudden change unleashed the coronavirus on a population of 1.4 billion people who had barely been exposed to it over the winter, raising fears that the outbreak could spark a new variant of concern and impact dozens of countries, including the United States, to test travelers from China and impose other restrictions.
But the China-funded study, published in The Lancet, found that of the 413 infections sampled in Beijing, all belonged to existing Covid variants. The most common were the omicron subvariants BA.5.2 and BF.7, which together accounted for more than 90% of local infections.
The samples were randomly selected for genomic sequencing from a larger pool of 2,881 high-quality samples collected in Beijing between November 14 and December 20, 2022.
George Gao, lead author of the study and a professor at the Institute of Microbiology of the Chinese Academy of Sciences, said it was important to examine whether new variants had emerged during the outbreak in China, given the impact other variants such as delta and omicron have had on the course of the pandemic.
“Our analysis suggests that two known omicron subvariants – rather than novel variants – have been mainly responsible for the current surge in Beijing, and probably China as a whole,” said Gao, the former director of China’s Center for Disease Control and Prevention. . in a press release.
“However, with the continued large-scale spread of Covid-19 in China, it is important that we continue to monitor the situation closely so that any new variants are found as soon as possible.”
While the study covered a short period at the start of the outbreak and sampling was limited to Beijing, the findings are in line with reports from Italy and other countries that tested arrivals from China for Covid and sequenced the results, Tongai Maponga said , a researcher in the Department of Medical Virology at Stellenbosch University in South Africa.
“Whatever they find in travelers coming from China is the same as what we already know is circulating elsewhere,” said Maponga, who was not involved in the Beijing study.
The investigation was also limited by the fact that China ended mandatory large-scale testing in December, making it difficult to know the total number of cases of the outbreak and, therefore, what percentage of the total number of cases the samples represent.
After being held at bay for most of the pandemic, the virus appears to have ripped through China much faster than in many other countries, beginning to gain momentum last fall, even before Covid restrictions were lifted. Beijing and other major cities experienced some of the first outbreaks.
Zeng Guang, a former chief epidemiologist at China’s CDC, said in late December that more than 80% of Beijing residents had most likely contracted the virus. A study published in January by researchers at the University of Hong Kong said it could be over 92% by January 31.
Chinese officials say a feared surge during the Lunar New Year holiday season, when hundreds of millions of people travel to their hometowns to visit relatives that began in mid-January, has not materialized. But the outbreak has still been a huge source of fear for Chinese who had learned to fear Covid-19 and devastating for those who have lost loved ones to the disease.
Global fears that a new variant could emerge were exacerbated by what the World Health Organization and others said was a lack of data from China on the outbreak. China has defended its data, criticizing the travel measures as unscientific and discriminatory.
Chinese officials have released more data in recent weeks, saying hospitals have recorded about 80,000 Covid-related deaths since early December. Many experts say the true number is much higher, with UK forecaster Airfinity estimating 608,000 deaths between December 1 and January 17.
China’s CDC last reported 3,278 Covid-related deaths nationwide from Jan. 27 to Feb. 2, about half the number from the previous week. It says daily Covid infections peaked at 6.94 million on December 22 and have since fallen to about 24,000 on January 30.
Maponga pointed out that a new variant of concern could still emerge anywhere in the world, highlighting the need for ongoing testing, genomic surveillance and transparent data sharing.
“As long as it continues to circulate and infect both humans and animals, the virus will always develop mutations, because that’s the nature of viruses,” he said.
This article was originally published on NBCNews.com