Background and Aim: Although Australia was verified by the WHO as having eliminated endemic measles in 2014, it likely achieved elimination at least a decade earlier. Regular travel-related reintroductions continue to occur. Some other high-income countries have recently lost or are at risk of losing their measles elimination status. We estimated Australia’s age-specific measles susceptibility to inform strategies to maintain elimination.
Methods and Analysis: We used data from nationally representative seroprevalence surveys for people born 1920–1960 (infection-acquired immunity) and born 1961–1999 (infection/vaccine-acquired immunity). For people born 2000–2018 (vaccine-acquired immunity only), we estimated measles susceptibility from coverage of one/two doses of measles-containing vaccine (MCV) from the Australian Immunisation Register and presumed vaccine effectiveness, adjusting for 0·04% waning of protection/year. We compared estimated age-specific susceptibility with laboratory-confirmed measles by birth cohort across 2008–2022 from the NNDSS.
Outcomes: Birth cohort susceptibility increased from 1% across those born 1920–1960 to 11% for the 1993–1995 birth cohort and ranged from 7–14% for those born 2000–2015. We estimated 1·7 million Australians (6·6%) were susceptible to measles in 2019 (95% UI: 1·3–3·2 million). Our estimated susceptibility distribution by birth cohort aligns with measles notifications and coverage patterns, with age groups over 40 years accounting for <1% and 15–35 years for ∼50%.
Conclusion and Future Action: Our estimate of all-age immunity to measles of 93.6% is at the lower end of the oft-quoted threshold for herd immunity of 93–95%. Age-specific immunity is consistent with immunisation schedule changes, MCV coverage trends and steadily diminishing boosting from circulation of wild-type measles in the post-vaccine era. Our estimate provides baseline data while highlighting the need for updated and more precise estimates of age- and geography-specific immunity gaps, and greater insight into waning immunity in the previously immunised.
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- Australia’s population susceptibility to measles in 2019
- Zoe CrokerHelen QuinnAngus McLureStephen LambertAditi DeyAlexis PillsburyPeter McIntyreKristine MacartneyFrank Beard
- Paediatrics and Child Health (DSM)
- Australian and New Zealand journal of public health, Vol.50(Supp. 1), 100508
- Elsevier
- 13/06/2026
- Communicable Diseases & Immunisation Conference 2026 (Melbourne, Australia, 15/06/2026–17/06/2026)
- Copyright © The Author(s) 2026. This work was first published in Australian and New Zealand Journal of Public Health (Elsevier). This is an open access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial use, distribution and reproduction in any medium, provided the original work is properly attributed to the creator(s) and the source, is not altered, transformed, or built upon in any way, and a link to the Creative Commons license is provided.
- English
- Conference proceeding; Conference Abstract