Measles protection gap grows as travel increases
17 Aug 2026
A study led by the National Centre for Immunisation Research and Surveillance (NCIRS) found that about 6.7% of Australians were susceptible to measles in 2019, equivalent to around 1.7 million people.
Published in the Australian and New Zealand Journal of Public Health, the research combined Australian Immunisation Register data with several serosurveys to assess measles susceptibility across different age groups.
The researchers estimated that Australia’s overall population immunity was 93.3% in 2019. This was within the World Health Organization’s estimated 93–95% range needed to maintain measles herd protection, but researchers warned that the safety margin is relatively small.
Lead author and epidemiologist Zoë Croker said Australia needs continued vaccination efforts to maintain its measles elimination status, which has been in place since 2014.
She also warned that population immunity may now be lower than the 2019 estimate because childhood vaccination coverage has fallen since the COVID-19 pandemic.
Several countries, including Canada, Spain and the United Kingdom, have recently lost their measles elimination status amid increasing outbreaks and international travel.
Australia has also recorded more measles cases linked to overseas travel, with total reported cases increasing since 2022. So far this year, 112 cases have been reported.
Babies who are too young to receive their routine measles vaccinations are among those at greater risk. Adults born from the late 1970s onwards may also have lower protection because vaccination schedules have changed over time.
Researchers are encouraging GPs to discuss measles vaccination status with patients planning overseas travel, particularly those travelling to countries where measles is circulating.
For infants aged six to 11 months travelling to areas where measles is present, an early measles vaccine dose may be recommended. These children should still follow the routine vaccination schedule after returning.
Although measles is often viewed as a childhood illness, adults continue to account for many cases. Some adults may have received only one dose of measles vaccine or may not have been vaccinated.
The researchers say Australia is not facing an immediate threat to measles elimination, but maintaining high vaccination coverage remains important, particularly as international travel increases.
Measles protection gap grows as travel increases
Source: National Centre for Immunisation Research and Surveillance (NCIRS), Australian and New Zealand Journal of Public Health.