China has recently seen a spike in respiratory illnesses, especially among children, that has prompted the World Health Organization (WHO) to ask for more details from the Chinese authorities. The health officials in China have attributed the increase in cases to various pathogens, such as influenza and mycoplasma pneumoniae, a common bacterial infection that typically affects younger children.

According to the Chinese Centre for Disease Control and Prevention, the country reported 209 new severe cases and 24 deaths from respiratory diseases in October, mostly caused by the strains of XBB variants, a new type of coronavirus that emerged in China earlier this year. The XBB variants are highly contagious and have been detected in several provinces, including Beijing, Hebei, Henan, and Shandong.

Epidemiologists warn of ‘immunity debt’ due to zero-Covid policy

Some epidemiologists have warned that China’s zero-Covid policy, which was implemented since the beginning of the pandemic and only lifted in December 2022, may have lowered the natural levels of immunity to respiratory viruses in the population. This could lead to a larger wave of infections in the winter months, as people are more exposed to different pathogens.

China’s zero-Covid policy involved strict lockdowns, mass testing, contact tracing, and quarantine measures to prevent any local transmission of the virus. However, this also meant that many people, especially young children, were not exposed to common respiratory viruses, such as rhinovirus, adenovirus, and respiratory syncytial virus (RSV), which usually circulate in the community and cause mild symptoms.

This phenomenon, known as ‘immunity debt’, has been observed in other countries that adopted similar strategies, such as Australia and New Zealand, where large outbreaks of RSV and other respiratory infections occurred after the easing of Covid restrictions. These infections can cause severe complications, such as bronchiolitis and pneumonia, especially in children under five years old.

China urges vaccination and prevention measures for respiratory diseases

In response to the spike in respiratory illnesses, China has urged the elderly and vulnerable groups to get vaccinated as soon as possible, as well as to follow the basic prevention measures, such as hand-washing, mask-wearing, and staying at home when ill. The country has also ramped up its surveillance and testing capacity for respiratory pathogens, and has provided guidance and training for primary health care institutions to diagnose and treat respiratory diseases.

China has also launched a nationwide campaign to promote the awareness and prevention of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, which affect more than 100 million people in the country. The campaign aims to improve the screening, diagnosis, and management of these diseases, as well as to reduce the risk factors, such as smoking, air pollution, and occupational exposure.

The WHO has said that it has requested more information from China about the clusters of pneumonia in children in northern China, and that such requests are ‘routine’. The WHO has also praised China for its transparency and cooperation in sharing the genetic sequences and epidemiological data of the XBB variants, which have been classified as ‘variants of interest’ by the global health body.