NATURAL HOLISTIC MEDICINE BLOG - A significant new study has identified that an estimated 1.7 million Australians are susceptible to contracting measles, based on comprehensive data from 2019. The paper, which is being published today in the Australian and New Zealand Journal of Public Health, serves as a stark warning for the nation’s immunisation strategy.
According to the National Centre for Immunisation Research and Surveillance (NCIRS), almost 7 per cent of the entire Australian population was susceptible to the highly contagious disease in 2019. This finding has prompted urgent calls for travellers and adults in high-risk age groups to verify their vaccination status immediately.
The Findings of the NCIRS Study
The research represents the most comprehensive national estimate of measles immunity currently available to public health officials. By combining blood samples tested for measles immunity with existing vaccination data, the authors have created a robust picture of the country's current health landscape.
Lead author Zoë Croker highlighted that the susceptibility is particularly concentrated among key age groups of Australians born from the late 1970s onwards. These findings are concerning, as they suggest that significant portions of the population remain exposed to a preventable yet dangerous disease.
“The concern is that there will be more measles outbreaks that will be harder to contain,” Ms. Croker explained regarding the potential public health impact. She further warned that if susceptibility remains unaddressed, the country will likely see more cases and a higher statistical chance of death associated with the virus.
Herd Immunity and the 93 Per Cent Threshold
The analysis revealed an overall measles immunity rate of 93.3 per cent, a figure that experts argue must be treated as a serious warning sign. Epidemiologist Adrian Esterman from Adelaide University emphasized that the nation cannot afford for this coverage to deteriorate any further.
The World Health Organization (WHO) mandates a target of 93-95 per cent vaccine coverage to successfully establish herd immunity and effectively prevent the spread of measles. When coverage falls below this threshold, the public health system loses its ability to effectively chase down every individual case.
“We don't really want it to get any worse,” Professor Esterman noted, highlighting the fragility of the current immunity levels. The risk is that if herd immunity dips below this critical 93 per cent mark, measles will begin to circulate more prominently throughout the Australian community.
At-Risk Generations: Understanding the Vaccine Gaps
The study identified specific age cohorts with higher levels of susceptibility, including infants, young children, and adults aged 42-49, 31-33, and 25-26 years. Ms. Croker explained that these specific gaps are largely the result of generational shifts in previous immunisation programs.
“The biggest gaps are in people born around the year 2000, as well as those born in 1993, 1994 and 1995, which was when that second dose of measles-containing vaccine was introduced,” she detailed. The researchers also noted that those born between 1977 and 1983 are more likely to have received only a single dose, placing them in an early vaccine era vulnerability category.
Furthermore, individuals born during or since 1966 may be susceptible if they missed vaccination altogether or only received partial coverage. However, the study acknowledges that some people in these older cohorts may possess lifelong immunity resulting from natural childhood measles infections.
The Role of International Travel and Imported Cases
While Australia achieved measles elimination status in 2014, the country continues to record imported cases via overseas visitors and returning residents. National Centre for Immunisation Research and Surveillance (NCIRS) associate director Frank Beard emphasized that travellers face a higher risk of bringing the disease into the country.
Professor Esterman noted that individuals between the ages of 20 and 40 are particularly susceptible to catching the virus during overseas travel. He pointed to regions such as the Philippines, Vietnam, and Thailand, where large measles outbreaks have occurred, as common sources for imported cases.
“Almost all of those cases are coming from people who've gone to Asia... they come back and bring it with them,” Professor Esterman observed. In the current climate of increasing global outbreaks, Dr. Beard strongly encourages all citizens to check their official vaccination records before departing.
Urgent Calls for Medical Intervention
Dr. Frank Beard advises that if individuals cannot find concrete evidence of having received two doses of the vaccine, they should strongly consider getting vaccinated again. This sentiment is echoed by experts who believe the medical community has a pivotal role to play in reversing these trends.
There is a specific call to action for General Practitioners (GPs) to proactively manage the immunity status of their patients. “If a patient is going overseas and talks to a GP about what they need in terms of protection, the GP should immediately ask them, what's your measles status like?” Professor Esterman suggested.
The Risk to Infants and Vulnerable Populations
The threat is not limited to those in the identified adult age groups, as babies and young children remain at extreme risk. Since routine vaccinations are not administered until infants reach 12 months of age, they depend entirely on herd immunity to remain protected.
Additionally, those with reduced immunity and unvaccinated pregnant women are at heightened risk because they cannot receive the vaccine while pregnant. With childhood vaccination coverage declining for the fifth consecutive year in 2025, public health experts fear the situation will only intensify.
Ms. Croker stated that her latest paper may actually underestimate the current level of susceptibility given the recent drops in childhood immunisation rates. The situation presents an urgent challenge for health authorities to ensure coverage does not fall further.
The Threat of Localized Outbreaks
The fear among epidemiologists is that as coverage rates decline, the country will experience more and more outbreaks. Professor Esterman warned that the virus is incredibly infectious, noting that a single infectious person entering a room with non-immune individuals could infect 12 to 15 people very quickly.
These outbreaks are likely to occur in pockets of the population where coverage rates are significantly lower than the national average. “It does mean that there will be some pockets of the Australian population which have got much lower coverage than that, and that's where you start seeing these small outbreaks occurring,” Professor Esterman stated.
Ultimately, the researchers maintain that this data is a vital indicator that something in the current system requires immediate correction. Proactive health measures and increased public awareness are essential to preventing measles from becoming a prominent public health issue once again.
Frequently Asked Questions (FAQ)
What is the herd immunity threshold for measles?
The World Health Organization recommends a vaccine coverage of 93-95 per cent to establish herd immunity and effectively prevent the transmission of measles within a community.
Why are adults born between the late 1970s and 2000s more at risk?
These age groups often fall into gaps in vaccination programs, such as the introduction of the second dose in the mid-90s or being in the 'early vaccine era' where individuals may have only received a single dose.
How can I check my measles vaccination status?
If you do not have clear records of having received two doses of the measles vaccine, experts strongly encourage you to consult with a GP and consider getting vaccinated again.
Why is international travel a factor in measles outbreaks in Australia?
Australia often sees 'imported' cases where returning residents or overseas visitors bring the virus from countries experiencing large measles outbreaks, particularly in parts of Asia.
Why are babies and pregnant women at higher risk of measles?
Babies are not routinely vaccinated until 12 months of age, making them dependent on herd immunity. Pregnant women cannot be vaccinated during pregnancy, leaving them and their unborn children vulnerable.
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