An outbreak of measles cases connected to a high school is growing, with a state music festival for school children among the list of potential spreading spots.

South Australia’s chief public health officer Professor Nicola Spurrier said in an update on Monday that there were now five cases of measles in the outbreak, with the latest infection involving a teacher from the school.

It takes the total number of SA measles cases in 2026 to nine, more than in 2025 when seven people were infected.

The update told of the person listed as the latest case visiting a number of locations while infectious, including the Queen Elizabeth Hospital, a pharmacy at Fullham Gardens and Adelaide Entertainment Centre.

The Catholic Schools Music Festival 2026 was hosted at the Adelaide Entertainment Centre on September 23, when the infectious teacher was present.

Spurrier said that while there were “clearly a lot of children there… we still maintain very high vaccination rates for our children”.

“It’s a large, well-ventilated area,” she added.

The chief health officer was more concerned about the Queen Elizabeth Hospital as a contact site, “because you’ve got other vulnerable patients there”.

The infectious person was at the QEH for close to 24 hours.

Symptoms of measles start with fever, cough, runny nose, and sore eyes, followed by a blotchy rash which usually begins on the head and then spreads down the body.

Spurrier told ABC Radio on Friday that 93.3 per cent of South Australians were vaccinated against measles, but vaccination rates had fallen each year.

“There are some people who have decided not to vaccinate their kids, and those people need to think, ‘Should I actually be making that decision?’,” she said.

“One case of measles in an unvaccinated community will spread that to approximately 14 other people. They then would spread it to 14 other people. All those people would spread it to 14 other people, each one of them.”

Measles is a highly contagious serious infection which can be associated with complications which can be severe, including pneumonia and encephalitis.

“It is a day — 24 hours — before you actually get any symptoms, and that’s why it also spreads easily, ’cause you don’t even know that you’ve got it,” Spurrier said.

She encouraged people who had not had two doses of the measles vaccine to get vaccinated for free.

“I think there could be additional spread – that’s just the nature of it,” she said.

“But the way we stop it spreading further is by having a very highly vaccinated community, which we do have.”

A full list of exposure sites can be found on the SA Health website.

Spurrier said individuals who have been in the locations, at the specified times (particularly those who are not fully immunised), should be alert for symptoms over the next seven to 18 days following the time of exposure.

–InDaily