Four students at Brighton Secondary School have now tested positive for measles, prompting SA Health to establish a temporary vaccination clinic and issue new exposure warnings across metropolitan Adelaide.
The latest infections are linked to a teenager whose measles diagnosis was first reported on 14 September after returning to South Australia from overseas.
Three additional teenagers have since contracted the highly infectious disease, bringing the number of confirmed cases associated with Brighton Secondary School to four.
South Australia has now recorded eight measles cases in 2026 — the state's highest annual total since 2016. ABC News
SA Health concerned about further infections
South Australia's Chief Public Health Officer, Professor Nicola Spurrier, has expressed concern about the level of transmission associated with the outbreak.
Speaking on Friday, Professor Spurrier said health authorities do not normally see this degree of spread and warned that additional cases may already be developing within the school community.
Measles is one of the most infectious diseases known, with a single infected person capable of passing the virus to approximately 14 others in an unvaccinated population.
The virus spreads through the air and can infect people who have not had direct contact with the person carrying it.
Health authorities are urging South Australians to check their vaccination status, particularly those who may have visited the newly identified exposure locations. ABC News
New exposure locations across Adelaide
SA Health has identified several locations visited by the infected teenagers while they were contagious.
Anyone who attended the following locations during the specified periods may have been exposed to measles:
These locations were identified in SA Health's outbreak notice issued on Thursday, 24 September. Mirage News
The exposure warnings relate to the specified dates and times. They do not mean these locations remain unsafe to visit.
SA Health has advised that additional exposure locations may be identified as contact tracing continues.
Earlier exposure locations also remain relevant
The latest cases follow the initial infection reported earlier this month.
That teenager had recently travelled internationally, arriving in Adelaide from Singapore after previously travelling from the Maldives.
The original exposure warning included Adelaide Airport on 8 September, Brighton Secondary School on 9 and 10 September, and Adelaide Metro Bus 265 on 10 September.
The original school exposure periods were 8:45am to 3:45pm on Wednesday 9 September and 3:15pm to 4:30pm on Thursday 10 September.
The bus exposure was between approximately 4:30pm and 5:00pm, travelling from Stop 29 towards Marion Centre. Mirage News
Temporary vaccination clinic established
In response to the growing outbreak, SA Health and the City of Holdfast Bay established a temporary vaccination service for the Brighton Secondary School community.
The clinic operated at Brighton Masonic Hall, 1 Commercial Road, Brighton, between 2pm and 6pm on Friday 25 September.
The temporary service was intended to provide convenient access to measles vaccination for students, families and other members of the school community.
Brighton Secondary School principal Rhoni McFarlane encouraged the school community to follow health advice and ensure their immunisations were up to date.
The school has been working with health authorities as the outbreak develops. ABC News
What are the symptoms of measles?
Measles is a highly contagious viral infection that can initially resemble a common respiratory illness.
Symptoms generally begin around 10 to 14 days after exposure, although the incubation period can vary.
Early symptoms include fever, tiredness, coughing, a runny nose and sore or red eyes.
Several days later, a distinctive blotchy rash generally develops, beginning around the face or head before spreading down the body.
The infection can also cause serious complications, including pneumonia, middle-ear infections and inflammation of the brain, known as encephalitis.
Infants, pregnant people who are not immune and people with weakened immune systems can face an increased risk of complications. Healthdirect Australia
What should people who may have been exposed do?
SA Health is advising anyone who attended an identified exposure location and is not fully immunised to monitor for symptoms over the coming weeks.
Anyone who believes they may have been exposed should check their vaccination history and contact their GP for advice if they are unsure whether they are protected.
People who suspect they have measles should telephone their doctor before attending a medical practice or hospital.
This allows healthcare staff to arrange appropriate precautions and reduce the risk of exposing other patients.
People who have recently been exposed and are not immune should seek medical advice promptly. Vaccination or antibody treatment may be recommended for eligible contacts within specific timeframes after exposure. Mirage News
Are you fully vaccinated?
Two doses of a measles-containing vaccine provide the recommended protection against the disease.
Australia's National Immunisation Program provides the measles, mumps and rubella vaccine to children at 12 and 18 months of age.
South Australia also funds measles vaccination for eligible adults born during or after 1966 who have not received two doses.
People who received childhood vaccinations decades ago may be uncertain whether they received the complete course.
Those unsure of their vaccination history can contact their GP or immunisation provider or check their available records through the Australian Immunisation Register.
Professor Spurrier has also encouraged people who are uncertain about their vaccination history to seek advice about receiving another dose. Mirage News
Further cases possible as contact tracing continues
With four Brighton Secondary School students now confirmed to have contracted measles, SA Health is continuing its response to the outbreak.
The latest infections demonstrate that the initial imported case has resulted in further transmission within the South Australian community.
Health authorities have warned that other people may already be incubating the virus, meaning additional cases could emerge over the coming days and weeks.
For now, the message to South Australians is to check their vaccination status, monitor for symptoms if they attended an identified exposure location and seek medical advice if they become unwell.
Further information and updated exposure locations are available through the SA Health website.
BitWaves News will continue to follow developments in South Australia's measles outbreak and provide updates as new information becomes available.