Without measles immunisation ‘little spot fire’ outbreaks may become harder to control, experts warn
Australians are being urged to check they are fully immunised against measles after a number of outbreaks of the highly contagious virus.
Health authorities in New South Wales and Victoria alerted the public in May to three separate cases, all in travellers returning from overseas. There have been 35 confirmed measles cases across Australia so far in 2024, more than in all of 2023.
While public health workers have managed to contain these outbreaks to date, an immunisation expert with the University of Sydney, Prof Julie Leask, said the virus was so contagious that, without raised awareness of symptoms and immunisation, control may become harder.
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“At the moment it’s like a little spot fire and you can control it fairly quickly,” she said. “That ability to prevent local transmission is why we can say we maintain the elimination of measles in Australia.”
Experts have warned the ability to contain the virus may become trickier if precautions are not taken.
Children can be vaccinated with their first dose at 12 months old, and require a second dose at 18 months to achieve full immunisation. Infants travelling overseas to places where measles is circulating can be vaccinated for free from six months of age, and need two more doses starting at 12 months of age.
According to the Australian Immunisation Register, 92.6% of two-year-olds are fully immunised against measles. But the University of Sydney infectious diseases epidemiologist Associate Prof Meru Sheel said 95% coverage was essential for such a contagious virus.
“One case can lead to 18 to 20 new cases, so the minute you have a drop in immunisation coverage, it can find those pockets,” she said.
Associate Prof Frank Beard, an associate director of the National Centre for Immunisation Research and Surveillance, said the impact of the Covid pandemic on vaccine uptake in young children was relatively small in Australia compared with many other countries. Vaccination rates were especially poor in low- and middle-income countries including India, Indonesia, Pakistan and the Philippines.
Prof Allen Cheng, the director of Monash Infectious Diseases in Melbourne, agreed: “There are always sporadic cases of measles being acquired overseas, but post-pandemic the risk for travellers is higher because of falling measles vaccination rates in other countries.”
Cheng said the other group of concern were those born between 1966 and 1992, when only one dose of measles vaccine was used routinely in Australia. It is recommended this group makes sure to get a second dose, Cheng said.
Unlike older adults, this group was also less likely to have been exposed to the wild-type measles virus – those infected from it would also have boosted immunity, Beard said.
There have been previous significant outbreaks of measles, including in NSW in 2012 when at least 168 cases occurred due to local transmission.
But Sheel said that in 2012 more two-year-olds (92.6%) had received all vaccinations recommended for their age, compared with 91.2% now. While measles has never been eradicated due to its infectiousness, Australia was declared measles-free in 2014 due to an absence of local transmission.
Associate Prof Morgyn Warner, a microbiologist at Pathology Awareness Australia, said if a person suspected they or their child had measles, it was essential for them to isolate and notify their GP immediately so they could order a test.
Symptoms typically include a distinctive red rash, which usually starts on the face and spreads to the rest of the body, small white spots with a bluish-white centre inside the mouth, high fever, cough, runny nose and red watery eyes.
“Measles is not a disease of the past,” Warner said.
