Pneumonia cases in children are unexpectedly surging in the Netherlands at an alarming rate — at the same time as China continues to grapple with a tidal wave of respiratory illnesses threatening to overwhelm its hospitals.

Last week, 80 out of every 100,000 children in the Netherlands between ages 5 and 15 were treated for pneumonia, reported the Netherlands Institute for Health Services Research (NIVEL).

Pneumonia cases among tots ages 4 and under were also on the rise, jumping from 124 to 145 per 100,000.

This is the biggest pneumonia outbreak the Utrecht- based research institute has recorded in recent years.

For comparison, at the height of the flu season in 2022, there were 60 recorded cases of every 100,000 children in the 5-to-15 age group.

Neither NIVEL nor the National Institute for Public Health and the Environment in the Netherlands could offer an explanation for the sudden uptick in pneumonia cases among children.

It is unknown whether the worrying health trend seen in Europe was connected to the disturbing rise in mystery respiratory illnesses that were sweeping across parts of China.

The World Health Organization (WHO) and Chinese health officials argued that no new or unusual pathogens had been found in the pneumonia cases.

The surge in illnesses has been blamed on children contracting known viruses like the flu, rhinoviruses, the respiratory syncytial virus and the adenovirus, which they had avoided during the two years of COVID restrictions.

The strict lockdown rules were lifted in China at the end of 2022, making this the first post-COVID flu season in the county.

Medical experts in China have suggested that a lack of exposure to common viruses during the protracted lockdown has weakened the population’s immunity.

In the Netherlands, however, COVID-era measures have been gone for a long time now, raising questions as to what could have trigged this new surge in childhood pneumonia cases.

Distressing videos showing hospitals in Beijing and other parts of northern China crowded with sick children and their parents that have emerged in recent days set off alarm bells around the world.

The WHO had made the rare step of publicly asking Chinese health officials to provide data on clusters of pneumonia cases, which were found to be driven by known viruses.

“We asked about comparisons prior to the pandemic. And the waves that they’re seeing now, the peak is not as high as what they saw in 2018-2019,” said Maria Van Kerkhove, acting director of the WHO’s department of epidemic and pandemic preparedness and prevention. “This is not an indication of a novel pathogen. This is expected. This is what most countries dealt with a year or two ago.”

Questions have been raised about whether China’s government was covering up the initial stages of another pandemic, after being accused of bungling its response to the emergence of COVID at the end of 2019.