China's 'Mysterious' Pneumonia Outbreak -- What We Know So Far

WHO's ongoing investigation indicates a rise in respiratory illnesses among children in northern China since mid-October.

china pneumonia

Media reports of a “mystery” respiratory disease outbreak in China prompted the World Health Organisation to publicly ask the country for further details, even as the rest of the world remains on edge about another health crisis emanating from the country that witnessed the outbreak of COVID-19 in 2019, which later spiralled into a massive pandemic causing millions of deaths all over the world.

Local media reports revealed a notable surge in pneumonia cases, especially among children with hospitals running at maximum capacity. The WHO on Wednesday made an official request to Chinese authorities and asked for “additional epidemiologic and clinical information, as well as laboratory results from these reported cases” to ascertain if the disease was from an unusual or new pathogen.

WHO’s investigation so far

WHO has been monitoring the situation in northern China which has been witnessing an increase in respiratory illness in children since mid-October.

At a press conference on November 13, Chinese authorities highlighted a nationwide surge in respiratory illnesses, predominantly impacting children, and attributed the increase to the lifting of COVID-19 restrictions and the arrival of the cold season.

On November 22, WHO was alerted to “clusters of undiagnosed pneumonia” cases in Beijing through media and ProMED reports. ProMED (Program for Monitoring Emerging Diseases) is a global electronic reporting system for outbreaks of emerging infectious diseases. It provides early warnings and updates on various infectious diseases, helping to detect and respond to health threats worldwide.

It is the same system that sent out an alert on December 30, 2019 saying,  "Undiagnosed pneumonia - China (Hubei)" when COVID-19 was in its early stages.

Following the recent reports, WHO made an official request to China for detailed information on November 22.

On November 23, a virtual meeting was attended by WHO, the Chinese Center for Disease Control and Prevention, and the Beijing Children’s Hospital. The teleconference was facilitated by the National Health Commission and the National Administration of Disease Control and Prevention. The requested data was provided and it showed an increase in outpatient consultations and hospital admissions of children due to Mycoplasma pneumoniae pneumonia, a known pathogen, since May. Other viruses such as RSV, adenovirus, and influenza virus were also responsible for illness since October.

“Some of these increases are earlier in the season than historically experienced, but not unexpected given the lifting of COVID-19 restrictions, as similarly experienced in other countries,” the WHO statement read.

What are the Chinese authorities saying?

Chinese authorities believe there has been no detection of any unusual or novel pathogens or unusual clinical presentations, according to the WHO statement.

China has only experienced, “the aforementioned general increase in respiratory illnesses due to multiple known pathogens.”

They also stated that since mid-October, China has increased monitoring for respiratory illnesses, including new measures for viruses and bacteria. This includes checking for Mycoplasma pneumoniae for the first time.

The increased surveillance, “may have contributed to the observed increase in detection and reporting of respiratory illness in children,” they said.

What are experts saying?

Leading Dutch virologist Marie Koopmans told Reuters on Thursday, "There is a plausible hypothesis that this could be what we have seen in other parts of the world when (COVID-19) restrictions were lifted.”

Prof Francis Balloux of the University College of London Genetics Institute said in a statement posted on X, "China is likely experiencing a major wave of childhood respiratory infections now as this is the first winter after their lengthy lockdown, which must have drastically reduced the circulation of respiratory bugs, and hence decreased immunity to endemic bugs.”

“Other countries, including the UK, experienced big waves of respiratory infections and hospitalisations in kids during their first winter after pandemic restrictions had been lifted,” he added.

The Union health ministry of India on Friday said it is closely monitoring the outbreak of H9N2 and clusters of respiratory illness in children in northern China, PTI reported.

“There is a low risk to India from both the avian influenza case reported in China as well as the clusters of respiratory illness, it said. India, the ministry said, is prepared for any kind of exigency that may emerge from the current influenza situation in that country,” the statement read.

Public health advice

WHO says there are no specific travel restrictions or advice for people travelling to and from China as of November 23.

“In general, persons should avoid travel while experiencing symptoms suggestive of respiratory illness, if possible; in case of symptoms during or after travel, travellers are encouraged to seek medical attention and share travel history with their health care provider,” the statement read.

The health body recommends that Chinese residents maintain distance from people who are ill, wear masks, wash hands, and ensure that they are in areas with good ventilation.

What is pneumonia?

Pneumonia is a respiratory infection which impacts the lungs. It causes an inflammation in air sacs which can get filled with fluid or pus.  Pneumonia infections are relatively common and occur in overcrowded places like schools, colleges, residence halls, and military training areas. 


When an infected person coughs or sneezes, tiny droplets containing the bacteria are released. Inhaling these droplets can lead to infection in others. The primary treatment for Mycoplasma pneumoniae infection is antibiotics.