Four teenagers from Brighton Secondary School have tested positive for measles, having attended places including a shopping centre and a supermarket.
People who believe they may be infected with measles are advised to call their doctor before visiting any clinic.
A temporary vaccination service has been set up for a school community in Adelaide's southern suburbs after four students tested positive for measles.
SA Health issued a measles outbreak alert yesterday after three teenagers contracted the infectious disease.
The health authority said those cases were linked to a positive infection in another teenager reported on September 14, who had returned from overseas.
SA Health and the Holdfast Bay Council have established a temporary vaccination clinic for the Brighton Secondary School community, which will operate at the Brighton Masonic Hall on 1 Commercial Road at Brighton from 2pm-6pm on Friday.
South Australia now has eight cases this year, the highest since 2016.
SA Health said the teenagers were in multiple places while infectious, including a school and a shopping centre.
Measles takes seven to 18 days to incubate and two weeks for a rash to appear.
Two doses of a measles-containing vaccine are considered effective at preventing illness.
Professor Spurrier said measles had been increasing in countries that had before eradicated the disease, including the US, UK and Canada.