The Program for Monitoring Emerging Diseases (Promed), which was launched in 1994 by the International Society for Infectious Diseases (ISID), is the largest publicly-available surveillance system conducting global reporting of infectious diseases.
On Nov 21 (2023), Promed reported an epidemic of undiagnosed pneumonia in China, which overwhelmed children’s hospitals in Beijing, Liaoning and north China.
School classes in those areas were also cancelled or on the verge of suspension.
The report, which was based on information from Taiwanese digital television news channel FTV, quoted parents as saying the children had high fever, with many developing lung nodules, but no cough or other symptoms.
The parents also asked if the authorities were covering up the epidemic.
Incidentally, on Dec 30, 2019, Promed first alerted the world to a pneumonia of unknown cause, possibly related to a seafood market in Wuhan, China.
The global Covid-19 pandemic followed.
A familiar pattern
China has had a three-year zero-Covid strategy with massive lockdowns that were only lifted in January (2023).
In the weeks that followed, Covid-19 cases, hospitalisations and deaths skyrocketed in a country with low levels of immunity.
On Nov 13 (2023), China’s National Health Commission held a press conference to discuss the increase in respiratory diseases in the country since mid-October (2023).
Northern China has reported an increase in influenza-like illness, compared with the same period in the previous three years.
The authorities attributed the increase to the lifting of Covid-19 restrictions and the circulation of known pathogens.
It was unclear whether the pneumonias were associated with the overall increase in respiratory infections or were separate events.
On Nov 22 (2023), the World Health Organization (WHO) requested China for additional clinical, epidemiologic and laboratory information on the reported clusters of respiratory disease in children.
The WHO reported: “On Nov 23, WHO held a teleconference with Chinese health authorities from 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, in which the requested data were provided, indicating an increase in outpatient consultations and hospital admissions of children due to Mycoplasma pneumoniae pneumonia since May, and RSV [respiratory syncytial virus], adenovirus and influenza virus 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.
“No changes in the disease presentation were reported by the Chinese health authorities.
“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.
“They further stated that the rise in respiratory illness has not resulted in patient loads exceeding hospital capacities.”
Non-pharmaceutical interventions (NPIs), like the lockdowns implemented to slow the spread of Covid-19 in many countries, prevented seasonal pathogens from circulating.
This resulted in less opportunity for people to build up immunity against these microorganisms, a situation also known as “immunity debt”.
The increase in common respiratory diseases in the first winter after the NPIs were lifted was a familiar pattern in many countries.
For example, hospitalisations for influenza in the United States in November 2022 was the highest in that month since 2010.
As people, particularly children, got together and mingled, it was likely that single respiratory infections or co-infections would occur in a background of circulating viruses that could cause more severe disease.
As the lockdowns in China were longer and harsher than any other country, it could be anticipated that the exit waves of respiratory infections could be substantial.
And this is the first post-Covid winter since lockdowns in China ceased in January (2023).
A different trend
M. pneumoniae (also known as “walking pneumonia”) is a childhood respiratory tract infection with features of sore throat, fever, fatigue and a lingering cough.
Infections occur throughout the year globally, with epidemics every few years (one to three years for Europe).
NPIs against Covid-19 led to an abrupt ending of these epidemics with marked decline of M. pneumoniae infections globally in 2020-2022.
An increase in case numbers from January to September (2023) have been reported in Denmark, Switzerland, Wales, Slovenia and Singapore.
This was followed by media reports of cases in some European countries.
The M. pneumoniae infections in China are different as they are higher in number than the influenza and RSV infections seen in the post-Covid-19 winter surges in other countries.
This is surprising because bacterial infections are often opportunistic, usually taking hold after viral infections.
Antibiotic resistance may have contributed to this year’s high hospitalisation rate in China.
The resistance of M. pneumoniae to macrolide antibiotics in Beijing in 2008-2012 was between 70-90%.
Meanwhile, influenza and RSV infections fell globally in 2020-2021 due to the NPIs during the Covid-19 pandemic, but have bounced back since then.
Influenza is most severe in children below five years old, as well as senior citizens.
RSV can be severe in infants and senior citizens.
Vigilance needed
To date, the WHO and experts have been reassuring in their responses to the pneumonia surge in China.
If no known cause(s) were identified, this would cause concern. But several causes have been identified.
The virus with pandemic potential that worries many is avian influenza (i.e. bird flu), which can mutate to become easily transmissible to humans.
China has been the epicentre of avian influenza, which has also spread to Europe, the Americas and Africa.
Multiple human cases of avian influenza were reported in China this year (2023), involving the H5N1, H5N6, H3N8 and H9N2 viral strains.
Human avian influenza cases have also been reported in Cambodia this year (2023), as well as two outbreaks of the highly pathogenic A(H5N1) influenza in poultry farms.
The large and continual outbreaks of avian influenza in birds and mammals increases the likelihood of mutations and mixing of bird and human influenza genetic materials, which could lead to a new virus with pandemic potential.
It is vital to be vigilant, taking into account the increase in Covid-19 cases in Malaysia and the need for more detailed information about China’s pneumonia outbreak.
The WHO recommends general measures to reduce the risk of respiratory illness that include:
- Getting vaccinated against influenza, Covid-19 and other respiratory pathogens as appropriate
- Keeping a safe distance from ill people
- Staying home when ill
- Getting tested for infections and seeking medical care as needed
- Wearing face masks as appropriate
- Ensuring good ventilation, and
- Practising regular handwashing with soap and water.
When there are symptoms suggestive of respiratory illness, travel should be avoided.
If there are symptoms during or after travel, medical attention should be sought and the healthcare provider informed of the travel history.
The Health Ministry also has to be more forthcoming with information about its monitoring, surveillance, etc.
Dr Milton Lum is a past president of the Federation of Private Medical Practitioners Associations and the Malaysian Medical Association. For more information, email starhealth@thestar.com.my. The views expressed do not represent that of organisations that the writer is associated with. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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