No new COVID variants have emerged during China’s recent surge in cases, according to new analysis.

The country ended its strict zero COVID policy in December after rare protests threatened the regime’s authority, leading to a large outbreak and almost 60,000 confirmed deaths in just over a month.

Large numbers of infections have previously proved a dangerous breeding ground for new variants to emerge, from Gauteng province in South Africa to Kent in the UK.

But a study suggests two existing sub-variants of Omicron – BA.5.2 and BF.7 – are what drove China‘s case surge, accounting for more than 90% of infections in Beijing between 14 November and 20 December.

While the research was concentrated on the capital, the study’s authors say it represents a snapshot of the nationwide coronavirus outbreak due to the characteristics of the city’s population and how transmissible the virus is there.

Professor George Gao, from the Institute of Microbiology at the Chinese Academy of Sciences, said: “Given the impact that variants have had on the course of the pandemic, it was important to investigate whether any new ones emerged following the recent changes to China’s COVID prevention and control policies.

“Our analysis suggests two known Omicron sub-variants – rather than any new variants – have chiefly been responsible for the current surge in Beijing, and likely China as a whole.

“However, with ongoing large-scale circulation of COVID in China, it is important we continue to monitor the situation closely so that any new variants that might emerge are found as early as possible.”

The peer-reviewed study has been published in The Lancet journal.