A surge in paediatric respiratory infections in China, mainly related to respiratory illnesses and pneumonia, has been attributed to respiratory syncytial virus, influenza, Covid-19, and perhaps most importantly, say experts, mycoplasma – a main cause of “walking pneumonia”.
Last week, there were reports of an increase in hospital admissions, with many of the country’s paediatric medical centres crowded with sick children, reports Forbes.
The wave of pneumonia cases sweeping through parts of the country prompted the WHO to request details on possible sources, and thus far, Chinese officials say causal agents include known pathogens, such as mycoplasma, RSV, influenza and SARS-CoV-2.
Chinese health authorities told the WHO that the surge – mainly among children in the northern part of the country – was simply part of a continued rise in infections since the lifting of Covid restrictions.
Authorities have not detected “unusual or novel pathogens or unusual clinical presentations”, even in Beijing and Liaoning, where the recent reports had raised concerns, the WHO said last week, after asking China for “detailed information” on the rise in cases mentioned by posts on ProMED, an infectious disease news service run by the International Society for Infectious Diseases.
A report had cited “many, many” children being hospitalised.
“They don’t cough and have no symptoms. They just have a high temperature (fever) and many develop pulmonary nodules,” a source had said.
“The lobby of Dalian Children’s Hospital is full of sick children receiving intravenous drips. There are also queues of patients at the traditional Chinese medicine hospitals and the central hospitals,” said a Dalian Central Hospital employee last week.
“Patients have to wait in line for two hours, and we are all in the emergency department – there are no general outpatient clinics.”
MedPage Today reports that another source said the uptick was “consistent with reports of ongoing nationwide mycoplasma pneumoniae … going on for at least two months now”, adding that azithromycin and doxycycline “are effective, in at least the few cases I know of”.
But a moderator noted that the “radiographic abnormalities were described as pulmonary nodules, rather than the patchy infiltrates that are seen most commonly in mycoplasma pneumonia”. “Be that as it may,” the moderator continued, “microbes do not ‘read the book’ and may present in less typical ways.”
Forbes reports that frequently, the bacterial illness caused by mycoplasma is called “walking pneumonia” because symptoms are often relatively mild but can last for weeks.
It typically doesn’t require hospitalisation, but younger children with a nascent immune system may be at greater risk of developing more serious disease.
And while the reports from China of “overwhelmed” hospitals evoked memories of the beginning of the Covid-19 pandemic, this week, Maria Van Kerkhove, acting director of the WHO’s department of epidemic and pandemic preparedness and prevention, said “this is not the same situation that we were in in December 2019 and January 2020”.
Apart from China, South Korea and France are also having serious epidemics, and the suspected main culprit appears to be mycoplasma pneumonia.
In South Korea, confirmed cases of the illness more than doubled from mid October to mid November. According to a summary released by the Korean Agency for Disease Control and Prevention, 226 (96%) of the 236 hospitalised patients with acute bacterial respiratory infections during the second week of November had mycoplasma pneumonia.
Notably, 80% of new patients are children under five. The agency further suggested that the early onset of cold weather in Korea contributed to a “rapidly increasing” number of cases.
Cases of mycoplasma can occur at any time of the year, but tend to be more prevalent in winter. In the northern and southern hemispheres, during each respective winter there is almost invariably an uptick in common infections like influenza, colds (caused by a large number of different viruses) and respiratory syncytial virus, which also produces cold-like symptoms.
Bacterial infections follow a similar seasonality. They’re usually opportunistic, taking advantage of an immune system that has been weakened by a virus. So, for instance, influenza, RSV and the common cold can sometimes lead to bronchitis or pneumonia, infections of the upper and lower respiratory tract, respectively.
Some have cited Covid-19 as what’s giving rise to the surge in mycoplasma, in that the still widely circulating virus lowers people’s immune defences.
While there is evidence of immune dysfunction persisting for many months or longer in some who contract Covid-19, it’s unclear whether there is evidence of widespread immune impairment due to SARS-CoV-2 throughout the population.
Alternatively, others claim the rise in mycoplasma infections has been brought about by what is sometimes termed “immunity debt” as there was a reduction of seasonal illnesses during Covid-19 lockdowns.
Responding to the current situation in China, the WHO team specifically pointed to an “immunity gap created by the pandemic”.
Social distancing, less travel and other measures designed to prevent the spread of Covid-19 could have lowered immunological defences against diseases like flu and RSV, which in turn may have set the stage for opportunistic infections such as mycoplasma.
But there’s no consensus on the hypothesis advanced by the WHO team. In fact, experts have long expressed scepticism about whether there is a generalised immunity debt.
For one thing, how long post-infection immunity lasts varies from one virus to another. And for flu viruses, for example, infection in one season may or may not offer protection in the next, depending on how closely related the two strains are.
Moreover, the cyclical nature of waves of mycoplasma infection – there were an upsurge in 2011, 2015 and 2019 – suggests the current spike has little to do with a purported immunity gap.
The pathogen can be treated with various antibiotics, including azithromycin, tetracycline, macrolides and fluoroquinolones.
Meanwhile, no alarm in SA
The latest available surveillance report for variant tracking from the NICD (South African National Institute for Communicable Disease) has not flagged anything new, reports Daily Maverick.
Omicron and a handful of its sub-variants are still the dominant variants around. Surveillance also found a few cases of the latest Eris variant.
According to this report, the 2023 flu season ended around 10 July. While sporadic flu cases are still detected, numbers remain low.
Some RSV cases are being detected and there still are cases of pertussis in Gauteng, North West Province, Mpumalanga, Western Cape, KwaZulu-Natal and the Eastern Cape.
The WHO’s Van Kerkhove said the Omicron subvariant BA.2.86 has been upgraded from a variant under monitoring to a variant of interest, after a slow but steady increase in its global detection.
“However, we don’t see a change in severity,” she said, adding that they only have 3 000 sequences from around the world at this stage.
In South Africa, BA.2.86 constituted 16% of sequences in samples sent for analysis in August, 22% in September and 19% in October.
The Technical Advisory Group from the WHO issued this risk report for BA.2.86 last week: “BA.2.86 has been reported in multiple countries, and the prevalence has been slowly increasing globally. However, public health risk … is low at global level. Current population immunity globally remains highly cross-reactive to this variant, especially against severe disease but also against symptomatic disease, and therefore the emergence of this variant will unlikely add increased burden to national public health systems.
“BA.2.86 was classified as variant under monitoring on 17 August 2023 and based on updated information, BA.2.86 and its sub-lineages (including JN.1) are now being classified as a variant of interest (VOI).”
See more from MedicalBrief archives:
China records 60 000 Covid deaths in a month
Likely order of COVID-19’s symptoms — Large analysis of China cases
China accused of hiding Covid data link to animals
COVID restrictions loosen after countrywide protests in China