Scarlet fever case confirmed at Wellington school

A Wellington school is urging parents to be vigilant for signs of scarlet fever after confirmation of a case at the school.

By Mary Argue of RNZ

RNZ has seen a message from Brooklyn Primary School to parents, notifying them of the infection on Tuesday.

It said scarlet fever spread easily and asked the community to keep an eye out for symptoms as a precaution.

The school has been contacted for comment.

Health New Zealand said scarlet fever was a contagious bacterial infection, spread through airborne droplets from an infected person's coughing or sneezing.

University of Otago professor of public health Michael Baker said while scarlet fever was no longer the feared disease it once was, it still required treatment with antibiotics and could be "moderately serious".

Scarlet fever was one of several diseases caused by group A streptococcal infection, he said, which most people experienced as a severe sore throat.

Baker said the bacteria was mainly cause for concern for two reasons: There was an invasive strain – which was recently made notifiable due to its fatality risk – and because a strep A infection could lead to more serious illnesses, like rheumatic fever.

"As almost everyone will know, we have a big problem with rheumatic fever in New Zealand, and that's caused by a response to strep A, skin and throat infections," he said.

"Scarlet fever is part of that spectrum of illness.

"Children do get hospitalised with it, children and young people, but it's not as serious as some of the other [strep A] diseases."

Baker said there were some key signs.

"As the name suggests it has these two features. One is the fever and usually a sore throat, and the other is the distinct rash."

Generally, the sore throat had a sudden onset, Baker said, often with swollen lymph nodes in the neck, a fever, and headache.

He said the fine, red, sandpaper-like rash usually appeared half a day, to two days later. It often started in the neck, chest and under the arms, but could spread further, he said.

Baker said any child with those symptoms or an intensely sore throat should see a doctor.

While not exclusively a childhood disease, scarlet fever typically affected school-aged children between four and eight years old, he said, and, like many illnesses, the bacteria that caused it lived in the throat.

Why it turned into disease wasn't fully understood, Baker said.

"These are just peculiarities of how this bacteria interacts with our immune system and causes very different forms of illness in different age groups and also very different outcomes."

Baker said it was fortunate that scarlet fever was a less severe form, these days.

In the 1800s, scarlet fever was one of the biggest infectious disease killers of children in New Zealand, Baker said.

"We would have some years hundreds or even more than 1000 cases and scores of death."

He said it was a "feared disease" that could sometimes kill all the children in a single family.

"There are some really awful historic examples."

Baker said it was a carefully tracked, notifiable disease and before antibiotics there were limited treatment options.

Throughout the 1900s, the numbers declined, and by the 30s and 40s incidents and severity had dropped dramatically, he said.

Baker said scarlet fever stopped being a notifiable disease in 1996, so there was little recent data on reported cases.

He said one study in 2023, found 20 cases in Auckland that year, which suggested about 50 or more throughout New Zealand annually.

Baker said strep A bacteria deserved "a lot of respect" because it could change its behaviour over place and time,

There had been a surge in scarlet fever cases in the United Kingdom in the past decade, he said, adding it might be worth proactively returning the disease to the notifiable list in New Zealand.