Seven cases of COVID-19 subvariant JN.1 infection had been detected in the Chinese mainland as of December 10, the National Disease Control and Prevention Administration said on Friday.

JN.1, a mutated variant of BA.2.86, was initially identified in Luxembourg in August. Its proportion has rapidly increased in global circulating strains, rising from about 4 percent in early November to approximately 30 percent in early December.

By December 10, the variant had been identified in at least 40 countries worldwide, with the highest proportion in Europe and showing a rapidly growing trend in America and other continents. Currently, the main prevalent strains in China remain EG.5 and its subvariants.

Despite its current "extremely low" prevalence level, the administration warned that the JN.1 variant might become a dominant strain in the country due to the subsequent influence of international epidemic strains and imported cases.

According to studies, there is no significant difference in transmission between JN.1 and XBB variants, and vaccination against XBB.1.5 remains effective against the JN.1 variant, as per the World Health Organization.

The administration reported that the seven cases infected with the JN.1 variant are mild and asymptomatic. It added that symptoms caused by different variants are often similar, and the severity usually depends more on individual immunity. 

Based on available evidence, the variant poses a low risk to public health, it said.