Pneumonia in Young Children: Is the Chinese epidemic spreading ?

 

The short answer to this question is…yes, it already has.

First, some background….

World Health Organization (WHO) has been monitoring data from Chinese surveillance systems that have been showing an increase in respiratory illness in children in northern China this autumn.

In mid-November, China’s National Health Commission reported a nationwide increase in the incidence of respiratory diseases, predominantly affecting children. They attributed this seasonal increase primarily to the lifting of COVID-19 restrictions and known circulating pathogens such as influenza, Mycoplasma pneumoniae, respiratory syncytial virus (RSV). Also relevant was the continued prevalence of SARS-CoV-2 in the Chinese population. Both Mycoplasma pneumonia and RSV are known to affect children more than adults.

To follow up their report, WHO made an official request to China to provide additional epidemiologic and clinical information, as well as laboratory results from the reported cases and data about recent trends in circulating respiratory pathogens. A key purpose was to identify whether there have been “clusters of undiagnosed pneumonia” in Beijing and Liaoning, and if so whether these were separate events, or part of the known general increase in respiratory illnesses in the community. In particular, and for obvious historical reasons, it was to confirm the absence of any identified ‘novel’ pathogens.

Data provided by the Chinese authorities suggested that there had been an increase in outpatient consultations and hospital admissions of children due to Mycoplasma pneumonia-induced pneumonia since May 2023, and due to RSV, adenovirus and influenza viruses since October. Some of these increases were earlier in the 'respiratory season' than historically experienced, but not unexpected given the lifting of COVID-19 restrictions, as similarly experienced in other countries. We should remember that the Chinese lock-downs were far more draconian than anything experienced in the West, and the persistence of Xi’s ‘zero Covid’ policy ensured that the population were denied exposure to common pathogens for longest. We should thus expect a more pronounced and lengthy ‘immunity trough’ than in other parts of the world.

A key finding was that no unusual or novel pathogens or unusual clinical presentations, had been noted so far.

Mycoplasma infections of one sort or another have been with us since the dawn of humanity and will no doubt continue to plague us until we go extinct. The recent resurgence of that feared 19th Century killer, tuberculosis (also caused by a mycobacterium) in many parts of the world, including western Europe and the US is but one example of this organism’s persistent success in colonising us, and the damage it can cause.

This particular paediatric respiratory syndrome is not confined to China and has also been seen widely across the northern hemisphere this winter. So far it appears to be in line with expectations, given the prolonged period of Covid lockdown and other restrictions over the past three years, which has weakened our global immunity to commonly experienced pathogens such a mycobacteria and influenza.  This was predicted by epidemiologists following the ‘recovery’ from Covid, and is one of the unfortunate consequences of living in a ‘sea’ of opportunistic respiratory pathogens.

As of mid-December, the US CDC’s verdict is that, based on laboratory findings to date, the increases in paediatric pneumonia do not appear to be caused by a new virus or other pathogen. Instead, these increases are likely to have been caused by viruses and bacteria we would normally expect to see during the respiratory illness season. CDC will continue to work with state and local officials to monitor the situation. The view of the UK DOH appears to be in line with this, suggesting that no special measures are required – for now.

That said, we should by no means drop our guard….

For one thing, Covid itself is on the increase again. Rather than following the widely anticipated course of a virus becoming established as an endemic, and weakening in its ability to cause harm in the process, a worrying upward trend in the incidence of so-called ‘long Covid’ has emerged in the UK this autumn, and this shows no signs of abating. 

This does actually make sense in terms of viral evolution; SARS-CoV-2 is under little selection pressure to moderate its ill-effects, since the vast majority of human infections result in little or no restriction on host mobility or host-to-host virus transfer. Our principal defence against the more serious symptoms manifested by this virus is our immunity; this does not in any case prevent infection, and requires periodic top-ups to remain effective. We allow it to lapse at our own risk.

There is also little doubt that new and potentially more devastating pathogens will emerge in the medium term, given the decline in health outcomes likely to be experienced by our species, due to over-population and the anticipated exhaustion of resources over the coming decades. 

We should thus maintain vigilance on a national level, and ensure that the excellent work already undertaken at UK.Gov's direction by our NHS in vaccinating our population is also maintained….and properly resourced.

VJCW 20.12.23