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.

Background and aim: Australia has maintained endemic measles elimination since verification was first achieved in 2014. To support the maintenance of elimination status, and strengthen national preparedness, we conducted a ten-year review of measles epidemiology across Australia since elimination was achieved.

Methods and analysis: Measles cases notified to the National Notifiable Disease Surveillance System (NNDSS) between 1 January 2014 and 31 December 2024 were analysed in R by sex, age, seasonality, state/territory, country of acquisition, vaccination status, genotype, and cluster characteristics.
Outcomes: A total of 1,095 cases were notified in the period (average 0.4 per 100,000 population per year). Children aged <1 year had the highest notification rate (n=33, 3.8 per 100,000 population per year); however, adults aged 20–49 years comprised 57.2% of all cases (n=626). Among cases with known vaccination history (n=766), 66.9% were unvaccinated, 20.1% had received one MMR dose, and 12.1% had received two or more doses. Of overseas-acquired infections (n=493), the most frequent source countries were Indonesia (20.1%), the Philippines (16.6%), and India (10.5%). Most recorded clusters (93.6%) were seeded from outside Australia. Notifications commonly peaked following major school holiday periods.

Conclusion and future actions: The trends observed in this report indicate that young adult travellers who were unvaccinated or unsure of their vaccination status were the largest contributors to measles notifications in Australia from 2014–2024. Although these cases have not jeopardised Australia’s elimination status, they pose a risk to vulnerable groups, including immunocompromised people, pregnant people, infants too young for MMR vaccination, and communities with low routine vaccination coverage. In the context of declining two‑dose coverage at 24 months nationally (from 94.0% in 2020 to 91.4% in 2024), these findings highlight the need for strengthened pre‑travel public health messaging for adults and renewed efforts to restore routine two‑dose coverage to ≥95%.

Background and aim:
Declining immunisation rates and a resurgence of measles globally mean that countries that have eliminated endemic measles, like Australia, face an increased threat of importations. National immunisation coverage reporting relies on static timepoints, limiting insight into when children actually receive vaccines, potentially permitting invisible immunity gaps, leaving children susceptible between reporting points.

Methods and analysis:
A cross-sectional retrospective analysis was conducted using routinely collected Australian Immunisation Register data for children residing in Hunter New England, New South Wales, born from 1 January 2015 to 1 June 2019 as a quality improvement initiative. Coverage, age at immunisation, and on-time immunisation were described by demographic, geographic and age variables. Reverse survival analysis was used to determine age when cohort 95% MCV2 coverage was achieved. Cultural integrity was embedded through the involvement of two Aboriginal research team members, including a project leader.

Outcomes:
The analysis included 53,390 children. Measles coverage exceeded the national and international target of 95% MCV2 coverage, with coverage in Aboriginal children surpassing national rates for all children. Several smaller geographic areas and subpopulations had pockets of lower coverage. Younger cohorts had earlier immunisation, with timeliness maintained during the early COVID-19 pandemic period. On-time immunisation rates were high, and most children receiving measles immunisation late were immunised within six months of the schedule date. The 95% MCV2 coverage threshold was achieved at 1,582 days (52 months) of age.

Conclusions and Future actions:
Improving immunisation data availability, accessibility, and timeliness offers potential to better inform targeted local public health activity. This presentation will demonstrate how immunisation timeliness data analysis can be a useful adjunct to static coverage data in understanding immunisation protection. Attendees will be equipped to apply these methods to better understand immunisation patterns and guide targeted action.

Background and Aim
The World Health Organization (WHO) certified Australia as having eliminated measles in 2014. However, global resurgence of measles, exacerbated by COVID-19 pandemic impacts on immunisation programs worldwide, has led to increasing importations of measles into Australia, and loss of measles elimination status in some high-income countries. Overall population immunity in Australia has been estimated at 93.6% in 2019, towards the lower end of the WHO’s 93-95% herd immunity threshold range. It is therefore critical to identify and address sub-national immunity gaps to maintain Australia’s elimination status. Using data from the Australian Immunisation Register (AIR), we aimed to estimate area-specific susceptibility to measles in Australia for birth cohorts born 2000–2024.

Methods and Analysis
We estimated susceptibility to measles in 2025 by age group (<5, 5-<13, 13-<19 and 19-<26 years), state/territory and Australian Bureau of Statistics Statistical Area 3 (SA3), using AIR data as at 11 January 2026 and published estimates of vaccine effectiveness.

Outcomes:
The proportion of the study population susceptible to measles was greatest in young adults aged 19-<26 years (12.8%) followed by pre-school children aged <5 years (9.2%), secondary school-aged children aged 13-<19 years (8.4%) and primary school-aged children aged 5-<13 years (7.6%). There was little variation at state/territory level by age group, except for young adults where susceptibility ranged from 15.6% in Western Australia to 8.6% in Tasmania. However, susceptibility varied considerably at SA3 level, reaching 30.2% for pre-school children in the Noosa Hinterland and 28.5% for young adults in Surfers Paradise.

Conclusions and Future actions
There are significant measles immunity gaps in some areas of Australia, especially among pre-school children and young adults. These data should inform strategies and targeted interventions to address these gaps and maintain measles elimination.

Background and Aim: Shingles incidence has gradually increased in Queensland since 2010. Notably, Queensland has experienced a decline in shingles vaccination coverage, from 52.6% in 2022 to 45.3% in 2023. The National Immunisation Program transitioned its funded shingles vaccine from Zostavax to Shingrix on 01/11/2023. This study aims to assess uptake and analyse adverse events following immunisation (AEFIs) for Shingrix in Central Queensland and Central West since this transition to determine gaps and inform interventions to improve vaccine uptake.
Methods and Analysis: Shingrix vaccination data were extracted from the Australian Immunisation Register and AEFI notifications from the Notifiable Conditions System from 01/11/2023 to 31/05/2025. Aged care resident lists were collected from participating facilities. Data were analysed by age, sex, First Nations status and region. AEFI symptoms were coded for comparison.
Outcomes: A total 7,483 Shingrix doses were administered, with 3,125 individuals completing the two-dose course. Uptake was highest among those 80 years and over (67.0%), followed by 75-79 years (10.9%). In contrast, uptake in those 65-74 years was low (1.9%). Most First Nations vaccinations were completed in those 50-64 years (87.5%). Vaccination completion in Aged Care was low (20.6%). 19 AEFIs were reported (25.4 per 10,000 doses). Those 65-69 years experienced the highest AEFI rate (2,000 per 10,000), while those 80 years and over had the lowest AEFI rate (10 per 10,000).
Conclusion and Future Actions: Transition to Shingrix has seen increased vaccination coverage, especially those 75 years and over and First Nations individuals 50-64 years. Vaccine uptake in those 65-74 years, First Nations individuals 65 years and over, and Aged Care is low. A pilot Aged Care vaccination program is planned to improve vaccination rates in this population. AEFI rates remain consistent with expected safety profiles, with further monitoring warranted in those 65-69 years.

Background and Aim
Australian children are recommended two doses of a varicella-containing vaccine. However, only the first dose, scheduled at 18 months, is funded under the National Immunisation Program (NIP). We assessed first- and second-dose coverage across 2010–2022 birth cohorts and examined socioeconomic and geographic equity in second-dose uptake.

Methods and Analysis
This retrospective cohort study analysed Australian Immunisation Register data for 4,284,025 Medicare-registered children born 2010–2022. Coverage was assessed by birth year, jurisdiction, remoteness (Accessibility/Remoteness Index of Australia [ARIA++]), and socioeconomic status (Index of Economic Resources [IER] quintiles). Timeliness of first-dose receipt and cumulative second-dose coverage to age 14 (2010 cohort; n=342,385) were examined. Multivariable logistic regression quantified independent predictors of second-dose receipt.

Outcomes
First-dose coverage by 24 months increased from 81.3% (2010 cohort) to 92.2% (2018 cohort) but was lower (91.4%) for the 2022 cohort. By 60 months, coverage reached 96.0% in the 2019 cohort. Delayed first-dose receipt (≥19 months) increased from 20.0% (2010 cohort) to 33.0% (2022 cohort). Second-dose coverage by 24 months increased from 0.6% (2010 cohort) to 2.7% (2022 cohort), and by 60 months from 2.2% (2010 cohort) to 3.3% (2019 cohort). In the 2010 birth cohort, second-dose coverage rose from 0.6% at 24 months to 2.2% at 60 months and 3.3% by age 14. Second-dose coverage by age 14 was highest in the least disadvantaged IER quintile (4.2%) and in major cities (3.8%), and lowest in the most disadvantaged quintile (2.8%) and regional areas (1.9%).

Conclusion and Future Actions
Second-dose varicella coverage remains very low under the current unfunded model, with differences by socioeconomic status and remoteness. Whilst first-dose coverage remains above 90% in the 2022 birth cohort, delays in first-dose receipt are increasing. These coverage and equity data, alongside disease burden data, will inform policy assessment of a funded second dose.

Background and Aim
A single dose of varicella vaccine scheduled at 18 months of age was added to the National Immunisation Program in 2005. We describe impact on paediatric varicella and zoster hospitalisations and complications, and assess the immune status of hospitalised cases.

Methods and Analysis
Hospitalisations with varicella or zoster diagnosis (ICD-10-AM code B01.x or B02.x, respectively) in children aged <15 years, between 2002–2022, were obtained from the AIHW National Hospital Morbidity Database. Complications and immunocompromising conditions were defined using ICD-10-AM codes. We calculated rates by age group and time period, and the proportion hospitalised with a complication or immunocompromising condition.

Outcomes
Varicella hospitalisation rates declined sharply following vaccine program introduction. In 2020–2022, rates were 92%, 97%, 92% and 77% lower than 2002–2005 in children aged <18-months, 18–59-months, 5–9-years and 10–14-years, respectively. The largest reduction in zoster hospitalisation rates occurred in the 18–59 month and 5–9 year groups (88% and 90% lower, respectively, in 2020–2022 vs 2002–2005).
The rate of complicated varicella hospitalisation fell from 10.3/100,000/year in 2002–2005 to 0.8/100,000/year in 2020–2022; the proportion with complications decreased more modestly (52.8% to 46.4%). Complicated zoster hospitalisation rates also declined, particularly in 18–59 month and 5–9 year olds, although the proportion with ocular, neurologic and skin complications increased over time.
The proportion of varicella hospitalisations with an immunocompromising condition rose from 7% in 2002–2005 to 16% in 2020–2022, while this proportion for zoster hospitalisations declined from 39% to 16%.

Conclusion and Future actions
Substantial declines in varicella and zoster hospitalisations and complications across all paediatric age groups demonstrate the long term impact of the vaccination program. The increasing proportion of immunocompromise among children hospitalised with varicella and zoster highlights the need for strategies, such as funding the second dose of varicella, to provide better herd protection for vulnerable subgroups.