China says no unusual or new pathogens have been detected in the upsurge in child respiratory illnesses in the north, the WHO said Thursday after pressing Beijing for detailed information.

Since mid-October 2023, the World Health Organization has been monitoring data from Chinese surveillance systems showing an increase in respiratory illness in children in northern China.

The UN health agency announced late Wednesday it had made an official request to Beijing for more data, but the government offered no public comment on Thursday.

The WHO said it held a teleconference on Thursday with the Chinese Center for Disease Control and Prevention and the Beijing Children's Hospital, facilitated by the National Health Commission and the National Administration of Disease Control and Prevention.

"Chinese authorities advised that there has been no detection of any unusual or novel pathogens or unusual clinical presentations, including in Beijing and Liaoning, but only the aforementioned general increase in respiratory illnesses due to multiple known pathogens," the WHO said in a statement.

"They further stated that the rise in respiratory illness has not resulted in patient loads exceeding hospital capacities.

"WHO is closely monitoring the situation and is in close contact with national authorities in China. WHO will continue to provide updates as warranted."

The organisation recommended that people in China follow measures to reduce the risk of respiratory illness.

These include recommended vaccines against flu, COVID-19 and other respiratory pathogens; keeping distance from people who are ill; staying home when ill; getting tested and medical care as needed; and wearing masks as appropriate.

"WHO does not recommend any specific measures for travellers to China," it added.

Next month marks the fourth anniversary since the outbreak of COVID-19 in Wuhan, China, was first reported.

Over the course of the COVID-19 pandemic, the WHO repeatedly criticised Chinese authorities for their lack of transparency and cooperation.

More than three years after cases were first detected in Wuhan, heated debate still rages around the origins of COVID-19.