Chinese health authorities told the World Health Organization (WHO) that a surge in respiratory illness among children in the northern part of the country is 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 recent reports had raised concerns, the on Thursday.
On Wednesday, the global health body had " on a rise in cases mentioned by posts on ProMED, an infectious disease news service run by the International Society for Infectious Diseases.
A on Tuesday said that children's hospitals in Beijing and Liaoning -- two cities in northern China that are about 500 miles apart -- are "overwhelmed." A Beijing citizen cited in the report said "many, many" children are hospitalized.
"They don't cough and have no symptoms. They just have a high temperature (fever) and many develop pulmonary nodules," the source said.
A the following day cited another source who said the uptick is "consistent with reports of ongoing nationwide Mycoplasma pneumoniae ... going on for at least 2 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."
Officials from China's National Health Commission had previously reported an increase in respiratory illness in the country during a press briefing on November 13, . Chinese officials attributed the rise to the lifting of COVID restrictions and circulation of pathogens such as influenza, Mycoplasma pneumoniae, respiratory syncytial virus (RSV), and SARS-CoV-2.
Mycoplasma pneumonia and RSV are known to affect children more than adults, the WHO noted. Still, it wasn't clear whether the new cases were "associated with the overall increase in respiratory infections previously reported by Chinese authorities, or separate events."
So on Wednesday the agency for epidemiologic and clinical information, along with lab results from these clusters among children. It also requested further information about recent trends in the circulation of known pathogens and the current burden on healthcare systems.
On Thursday, WHO held a teleconference with health officials from the Chinese Center for Disease Control and Prevention and the Beijing Children's Hospital. The meeting was facilitated by China's National Health Commission and the National Administration of Disease Control and Prevention.
WHO said the requested data were provided, and they indicate an "increase in outpatient consultations and hospital admissions of children due to Mycoplasma pneumoniae pneumonia since May, and RSV, adenovirus, and influenza virus since October."
Some of these increases are earlier in the season than is typical, "but not unexpected given the lifting of COVID-19 restrictions, as similarly experienced in other countries," according to the WHO statement.
Chinese authorities said they didn't detect any unusual or novel pathogens or unusual clinical presentations, including in Beijing and Liaoning, WHO said.
Authorities also said the rise in respiratory illness has not resulted in patient loads exceeding hospital capacity.
Experts in the U.S. say it's certainly possible that the surge is due to pathogens hitting an immune-naive population hard, following the lifting of China's zero-COVID policy at the start of this year.
"This is likely to be a cluster of ordinary respiratory pathogens that have all coincided, similar to what happened in the United States last year," Amesh Adalja, MD, of the Johns Hopkins Center for Health Security, told MedPage Today in an email. "However, it is important to characterize these cases, and to understand what pathogens are behind them."
"Any cluster of respiratory infectious disease should be rapidly investigated," Adalja added. "The Chinese government and public health authorities should be very transparent about what diagnostic tests are being done, and what those results are."