On the China outbreaks of respiratory illness I can say that while it’s natural in these days to be concerned about any new respiratory disease outbreak, cases occurring in China at present are not considered unusual by WHO. 

There has been an uptick in the rates but it is that time of year and China has implemented a new national reporting system that has, as it should, picked up cases that were not reported under the old system. 

We have seen this phenomenon in many countries as they have improved public health surveillance after COVID. If there is a real public health concern at present it would be monkeypox in Africa.

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. 

There has also been a surge in well recognised infections including influenza, RSV and Mycoplasma pneumoniae.

The observed increase in children with respiratory virus infections in China, seems to reflect a surge in common respiratory virus infections (RSV, rhinovirus, influenza etc.) due to the onset of winter. This is not unexpected and probably reflects the 'immune deficit' effect of strict COVID lock down policies that prevented exposure to common viruses (and the acquisition of protective immunity) in young children.  

We are currently waiting for more information and updates, but there is no indication that this represents an outbreak of a novel unidentified virus - as reported by some outlets. 

It also shines a light on the need for better global surveillance systems and improved communication between public health authorities globally.

The WHO has been monitoring data from China that is suggesting an increase in respiratory illnesses such as pneumonia. Understandably some may see this as a concern, however at this stage there is too little information to draw any firm conclusions. Spikes in respiratory conditions do occur for many reasons including seasonal variations.

In the case of China which was in lock down for significant period of time, it may simply be community acquired due to increase in socialisation. The very preliminary data is suggesting that nothing out of the ordinary is seen, as the cause of the pneumonia illness have been varied, including influenza, RSV etc. At this stage there is nothing to suggest that it may a new variant of COVID. One thing to note is that we can be reassured that the surveillance processes are working, which is a very good thing.

"A rise in cases of an unknown illness in China is being investigated by health officials, with children being hospitalised with pneumonia. Although the circumstances are not entirely clear, there is a believe that these outbreaks are likely attributable to a resurgence of familiar respiratory pathogens following the strict coronavirus lockdowns in the country, rather than stemming from a new infection.

Why now? With Beijing battling cold weather, the surge in respiratory infections has coincided with the city's recent plunge into extreme cold temperatures. While there is need for caution, we should not panic and remain calm. The winter in China marks the first season following the implementation of stringent COVID-19 lockdowns, where there is a higher population of children who haven't encountered certain viruses and bacteria, lacking immunity as a result.

Individuals who were previously infected by these pathogens may experience a decline in immunity over time. This sets the stage for a potential significant surge in infections, similar to what has been observed in other countries post-lockdowns.

What do we know so far? Children affected by this ‘pneumonia’ illness are presenting with elevated temperatures and lung inflammation, which is distinct from a typical pneumonia symptom as it is presenting without cough. These symptoms resemble those seen in flu or respiratory virus diseases such as RSV, Influenza and possibly Mycoplasma pneumonia. Numerous children are being admitted to hospitals, displaying no cough or other noticeable symptoms besides a high temperature, and many are developing pulmonary nodules. Despite the notable increase in cases, there have been no reported deaths as of now.

Is there another pandemic on the horizon? While extreme caution and steps must be in place to mitigate the current situation in China, currently, the majority of the people who are affected with this undiagnosed pneumonia are children. 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. Having said that, further diagnosis can only be made until detailed information on an increase in respiratory illnesses and reported clusters of pneumonia in children are being presented by the Chinese authorities."

The statement released by WHO suggests the pressure on the health system from a surge in childhood pneumonia is related to mixed infections from RSV, influenza, mycoplasma, COVID and adenovirus, and not a novel pathogen. It is close to winter, so expected that there would be an increase in respiratory pathogens.

Mycoplasma outbreaks have been reported for several weeks now in China, and we have followed this closely through our early warning system, EPIWATCH. It is unusual for mycoplasma to cause hospital overload, and usually, this is treated in the community.

Influenza can certainly cause pneumonia and be very severe, even fatal in young children. RSV and SARS-CoV-2 can also be severe. It is also possible to get co-infection in an individual with more than one pathogen. It may be the simultaneous occurrence of all these epidemic infections which may be overloading hospitals.

Our data from EPIWATCH suggests respiratory illnesses and pneumonia are higher this year compared to the same time last year.

Beijing has very good surveillance, so would be in a better position to identify a novel pathogen than perhaps Wuhan. The dropping of COVID mitigations may well be contributing to this situation, but occurred almost a year ago now.

The widespread transmission of SARS-CoV-2 in China and globally may also be contributing to high rates of other infections, as there is now a large body of research showing SARS-CoV-2 can cause immune dysregulation that may persist after the acute infection. It may explain the unusual mycoplasma and other epidemics.

Reports from Taiwan also suggest a high rate of antibiotic resistance to mycoplasma, which may also be a factor causing increased hospital admission.

When the number of cases is small, we can see large variation in the number of reported cases just through random chance. At this stage, the outbreak appears to be contained to China, and there is no evidence of the outbreak spreading globally. This year has already seen an uptick in cases of RSV in Australia, and so seeing this appear in other global settings is within expectation.

As more data emerges on the current outbreak, we will quickly get a better picture of the rate of spread, and what controls, if any, may be required to keep the outbreak in check.

We have seen an increase in respiratory illnesses in many countries after lifting COVID restrictions. At this stage, Chinese authorities have also attributed this increase to the lifting of COVID-19 restrictions and to circulating known pathogens, including influenza and SARS-CoV2.

However, I think all these existing pathogens can easily be tested. If this increase is due to existing pathogens, then fine, otherwise rapid action is needed. We cannot afford a delay in the identification of any other epidemic/pandemic. Although Chinese authorities did not detect any unusual or novel pathogens, I am concerned about reports of 'undiagnosed pneumonia'. Previous major respiratory epidemics/pandemics also started like this. So at this stage, we don't need to panic, but enhanced surveillance and testing is needed.

This is the first winter with fully reopened international borders for China, and they have been experiencing uplifts in a range of infectious diseases, similar to that seen in other countries, including Australia, after opening up. The rise of infections in children is also not unexpected in the first winter with community-wide COVID-19 exposure alongside other winter pathogens circulating at higher levels than seen during the pandemic. The number of paediatric pneumonia cases, however, is what is concerning health authorities globally.

No new viruses or other pathogens have been reported by China to date, and there is also no indication that children are being hospitalised from COVID-19 related pneumonia to suggest a shift in Omicron subvariants or disease severity is contributing to the increased pneumonia reporting.

Mycoplasma pneumoniae, a small bacterium responsible for respiratory infections and believed to be a common source of community acquired pneumonia has also been included in China’s surveillance system for the first time in October this year, and outbreaks have been detected. A rise in influenza, adenovirus, and RSV has also been reported. 

RSV was a rising problem prior to the pandemic, and so it is not surprising that this has been one of the infections that has experienced a strong resurgence in many countries post opening up. 

Young children in school in China will have spent up to half their life without the usual exposure to common pathogens, and so do not have the same levels of immunity. Adults have also not had their immunity maturely boosted to the same degree in recent years and so susceptibility to these infections is elevated. Mothers are also less able to protect their babies when they aren’t carrying the same antibody levels to pass to their child through breastfeeding. 

A drop in immunity against common pathogens can lead to both more infections, and more severe disease when an infection occurs. The combination of both can lead to substantial rises in the number of people in hospital with infections. 

The main concern is if the rise in childhood pneumonia were to indicate a new pathogen, or new levels of disease severity. So far we have not heard reports of either, but it is important that the source of infection can be confirmed to rule out these concerns, and any possible implications outside of China.

A rise in viral respiratory tract infections in children at this time of year is not unexpected and is a phenomenon that has been observed over many decades worldwide at the onset of winter. However, in the context of the pandemic due to a relatively new virus such as SARSCoV-2 and the potential for other new viruses or mutations to cause respiratory tract illness, prompt reporting and monitoring are essential.

A key task is to compare the prevalence of viral respiratory tract infections in children with previous years, especially those prior to the pandemic, to determine whether or not the current peak is atypical or suggestive of a new strain. Post-pandemic, many countries saw slightly different seasonal patterns in viral prevalence which need to be taken into account, especially if the restrictions on social gatherings were only recently lifted in these parts of China.

If, however, normal social interactions have been occurring over the last year or more, which is true of most countries, then there is reason to be very watchful. China has identified the common organisms causing the increased outpatient consultations and hospital admissions of children being Mycoplasma pneumoniae, RSV, adenovirus and influenza; but it is important to observe whether these are occurring at a much higher rate than usual or whether there is another, as yet unidentified organism which could be responsible.

In the meantime, until we know more about this surge in children’s infections, we now know what to do to limit the spread of viral respiratory illnesses, as suggested by WHO. This includes having influenza and COVID-19 vaccinations, staying home when ill, wearing masks as appropriate, not gathering in crowded locations, ensuring good ventilation and practising regular handwashing.