Measles Cases Spike in NSW, Raising Concerns Over Undetected Community Spread
A concerning surge in measles cases has been observed in New South Wales (NSW), with health authorities particularly worried about the potential for the highly contagious disease to be spreading undetected within the community. In the initial three months of the year, NSW recorded 38 measles cases, a significant portion of which, five to be exact, have no identifiable source of infection.
Vicky Sheppeard, Director of the South Eastern Sydney Local Health District’s Public Health Unit, highlighted that the majority of these cases are linked to travellers returning from Southeast Asian countries. However, the five infections identified between January 1 and March 7 are particularly troubling as they cannot be traced back to known exposure sites or overseas travel. This suggests a worrying possibility of local transmission within NSW.
“That is of concern because there must have been undetected cases,” Dr. Sheppeard stated. “In order to prevent an outbreak, we need to identify all cases and make sure that all their contacts are followed up.”
Measles, a potentially fatal yet vaccine-preventable illness, typically presents with a fever, cough, and a distinctive rash that spreads across the entire body. While preventable, severe complications can arise, including middle-ear infections, diarrhoea, and pneumonia. In extremely rare instances, it can lead to a progressive and fatal brain disease known as subacute sclerosing panencephalitis.
Rise in Cases Linked to International Travel
Dr. Sheppeard explained that an increase in measles cases is often seen in the early months of the year, coinciding with the return of travellers from overseas. The current figures for 2026 represent a notable rise compared to previous years. This trend is attributed to significant measles outbreaks occurring in Southeast Asian nations such as Indonesia, Vietnam, and the Philippines, particularly in the wake of the COVID-19 pandemic.
“Australians love to travel to south-east Asia and do that frequently, particularly over the summer period,” Dr. Sheppeard commented.
The detected cases have been observed among Australians in their 20s and 40s. This demographic may be experiencing higher rates of infection due to potential shifts in vaccine schedules and past variations in childhood immunisation protocols. Historically, the measles-mumps-rubella (MMR) vaccine has been recommended with a first dose at 12 months of age and a second at 18 months. However, in January, the Australian Technical Advisory Group on Immunisation (ATAGI) updated its guidance to recommend an additional dose for infants aged six to 11 months undertaking overseas travel.
“In Australia, we’re really lucky we have had a long-standing national immunisation program that funds our vaccines,” Dr. Sheppeard added. “We’ve got a strong public health sector, we have Medicare and we have a national register, so that has enabled us to really maximise our coverage.”
Could Australia’s Measles-Free Status Be at Risk?
Australia was declared to have eliminated endemic measles by the World Health Organisation (WHO) in 2014. However, in recent years, a number of countries, including the United Kingdom, Spain, and Canada, have unfortunately lost their elimination status due to uncontrolled outbreaks and declining vaccination rates. The United States, which first achieved elimination status in 2000, is now reportedly on track to lose its status, with outbreaks identified in more than 40 states.
Catherine Bennett, Chair of Epidemiology at Deakin University, noted that Australia currently does not experience the same level of local transmission as seen in the United States or Southeast Asian countries. Nevertheless, Professor Bennett cautioned that if vaccination rates continue to decline and the public does not adequately respond to overseas outbreaks, Australia could indeed risk losing its measles-free status.
“If [cases] are all imported that’s telling us about endemic disease in other parts of the world that haven’t eliminated it,” she explained. “But if we have enough unvaccinated people and enough secondary cases in Australia particularly, that then start passing it on to other people — then it changes the whole dynamic.”
Professor Bennett pointed to the United States as an example where “local explosions” are occurring, not solely due to geographical factors, but also influenced by religious and cultural perspectives on vaccination. “If measles gets into part of the community where it starts to spread because there’s enough susceptible people who aren’t vaccinated or haven’t had a prior infection, then that’s when local transmission starts to take off,” she stated. “It’s a disease that, thankfully has a relatively low fatality rate, but the most fatalities occur in children.”
The Ultimate Defence: Robust Vaccination
Achieving herd immunity, a critical barrier against the spread of infectious diseases like measles, requires vaccine coverage of 92–94 per cent of the population, according to the Department of Health. Recent findings from the National Centre for Immunisation Research and Surveillance indicated a slight decrease in the coverage of the first dose of the MMR vaccine in children at 24 months of age, dropping by 0.4 of a percentage point between 2022 and 2023.
Terry Slevin, Chief Executive of the Public Health Association of Australia, described measles as the “canary in the coal mine” for infectious diseases. Adjunct Professor Slevin noted that while Australia has historically maintained high vaccination rates, these are now slowly declining and falling below the national target of 95 per cent.
“We know measles is a highly infectious disease and ultimately our best defence is a very, very effective vaccination regime,” he asserted. “In most cohorts, we have in excess of 90 per cent take-up, it’s slightly coming off from the target.”
Adjunct Professor Slevin further elaborated that preventing travel-related infections entirely is virtually impossible, especially given that measles often presents asymptomatically in its initial stages. “Australians travelling overseas or people coming from overseas into Australia, and bringing the infection with them — ultimately it comes down to issues relating to regions around the world having varying levels of vaccination,” he explained. “I don’t think there’s reason to be concerned about our disease-free status being removed as long as we respond to these challenges sensibly and continue to reinforce the importance and value of vaccination in Australia.”
