Key Points
- China is experiencing a rise in respiratory illnesses.
- Officials there say they have not detected any "unusual or novel diseases".
- Experts say the situation warrants close monitoring but are not convinced a new global outbreak is at hand.
Chinese officials say they have not detected any "unusual or novel diseases", the World Health Organization says (WHO), after an official request by the United Nations health agency for information about a spike in respiratory illnesses and clusters of pneumonia in children.
WHO cited unspecified media reports and a global infectious disease monitoring service, the Program for Monitoring Emerging Diseases (ProMED), as reporting clusters of undiagnosed pneumonia in children in northern China and formally requested more details this week.
As per the rule, China responded to the WHO within 24 hours. The WHO had sought epidemiologic and clinical information as well as laboratory results through the International Health Regulations mechanism.
What do we know about the increasing illnesses?
The emergence of new flu strains or other viruses capable of triggering pandemics typically starts with undiagnosed clusters of respiratory illness.
WHO noted that authorities at China's National Health Commission on 13 November reported an increase in respiratory diseases, which they said was due to the lifting of .
Other countries such as respiratory syncytial virus, or RSV, when pandemic restrictions ended.
WHO said media reports about a week later reported clusters of undiagnosed pneumonia in children in northern China.
The UN agency said it held a teleconference with Chinese health officials on Thursday, during which the data it requested was provided.
It showed an increase in hospital admissions of children due to diseases including bacterial infection, respiratory syncytial virus (RSV), influenza and common cold viruses since October.
"No changes in the disease presentation were reported by the Chinese health authorities," WHO said.
Although it's rare for the UN health agency to publicly ask for more detailed information from countries, as such requests are typically made internally, WHO China said it was "routine" to request information on increases in respiratory illnesses and reported clusters of pneumonia in children from member states, such as China.
The global agency decided to issue a statement on China to share available information, as it received a number of queries about it from media, WHO China said in an emailed statement.
The ProMED alert was based on a report by FTV News in Taiwan that came out on Tuesday.
What have experts said?
Outside scientists said the situation warranted close monitoring, but were not convinced that the spike in respiratory illnesses signalled the start of a new global outbreak.
Professor Robert Booy, an infectious diseases and vaccine expert at the University of Sydney and a consultant to vaccine manufacturers, said the fact that the only reported subjects are children indicates the illness isn't anything new.
"As this does not appear to be occurring in adults, that suggests that adults have prior immunity, which points to an existing pathogen as the likely cause, rather than anything new," he said.
"There has also been a surge in well recognised infections including influenza, RSV and Mycoplasma pneumoniae.
Vinod Balasubramaniam, a molecular virologist and leader of infection and immunity research strength at Monash University Malaysia's Jeffrey Cheah School of Medicine & Health Sciences, echoed this observation. He also noted, however, that more details were still needed.
"If these cases in China were being caused by a new pathogen, lots of adults should be getting ill too, as they would also have no previous exposure," Balasubramaniam said. "Having said that, further diagnosis can only be made once detailed information on an increase in respiratory illnesses and reported clusters of pneumonia in children are presented by the Chinese authorities."
Francois Balloux of University College London said China was probably experiencing a significant wave of childhood infections because this was the first winter since restrictions were lifted, which is likely to have reduced children's immunity to common bugs.
How is China responding?
China's National Health Commission did not immediately respond to a request for comment.
On Thursday, it published an interview with the state media agency Xinhua in which it advised parents what to do and mentioned that big hospitals were receiving a large number of patients and waiting times were long. It did not comment on the WHO notice.
Since mid-October, the WHO said northern China had reported an increase in influenza-like illness compared with the same period in the previous three years.
It said China had systems in place to capture information on trends in illness incidence and to report that data to platforms such as the Global Influenza Surveillance and Response System.
In recent days, media in cities such as Xian in the northwest have posted videos of hospitals crowded with parents and children awaiting checks.
Some social media users have posted photos of children doing homework while receiving intravenous drips in hospital.
The WHO said that while it was seeking additional information, it recommended that people in China follow measures to reduce the risk of respiratory illness.
Measures included vaccination, keeping distance from sick people, staying at home when ill, getting tested and medical care as needed, wearing masks as appropriate, ensuring good ventilation, and regular hand-washing, it said.
