Increase in pneumonia cases in NSW children prompts warning from health experts

A surge in pneumonia cases has seen large numbers of children in NSW emergency departments, prompting warnings from health experts.

The amount of school-aged children presenting to hospital with pneumonia symptoms has tripled compared to January, with 124 children aged four and under in emergency departments with pneumonia last week.

For those aged five to 16 years old, the numbers were even worse, with 317 presenting to emergency departments with pneumonia in the same week.

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Older teenagers and adults are also being infected, with 127 ending up in emergency rooms.

"We've certainly seen an increase above what we'd normally see at this time of year," Professor Philip Britton, from Westmead Children's Hospital said.

"We've got pretty good indications that there's one particular bug that might be accounting for a fair bit of it in those children.

"And that infection is a bacterial infection called mycoplasma pneumoniae."

Experts say the emergency room numbers are "almost certainly" an under-representation of pneumonia cases, with general practitioners also seeing a surge in cases.

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Britton said case numbers are surging because it's a new kind of bacteria that children haven't built immunity to yet.

"Now that it's come back, we've got a cohort of children who haven't seen this bug," he said.

"Their immunity's not been trained against it and so we're getting larger numbers getting a bit more unwell."

While case numbers are going up, it's known to be a generally less severe form of pneumonia.