Vaccine Coverage Indicators

A high level of vaccine coverage sustained over many years is required to achieve population level control of vaccine targeted HPV types, and in the long-term, cervical cancer elimination (1,2). For the purposes of monitoring coverage over time and comparing across countries, which vary in their age of vaccination within the range 9-14 years, WHO recommends the use of the indicator ‘HPV vaccination coverage by age 15 years' (3).

This indicator measures the proportion of the population turning 15 years in the reporting year who have received one (or more) HPV vaccine doses by age 15, noting that Australia moved to a single dose program in 2023. Prior to 2023, either two correctly spaced doses were required (2018-2022) or three correctly spaced doses (2007-2017).

The WHO target relates to female-only programs, which are the most cost-effective option. Australia has a gender-neutral program and has adopted a 90% both sex target (4). Modelling suggests the same impact on HPV burden as achieving 90% coverage in girls only could be achieved with less than 90% coverage of both sexes (5).

Nationally, in the cohort who turned 15 years in 2022, HPV vaccination coverage was 84.2% (85.3% in females and 83.1% in males). This was a decline from the historical peak achieved in the 15 year old 2020 cohort (85.7%, female 86.6%, male 84.9%). Coverage was lower amongst Indigenous adolescents at 80.5% (females 83.0%, males 78.1%) (reduced from 2021 cohort by 2.8% (female 3.1%, male 2.5%)) than non-Indigenous (84.4% overall; female 85.5%, male 83.4%) (reduced from 2021 cohort by 1.0% (female 0.8%, male 1.2%)).  This was a decline from the historical peak achieved in the 15 year old 2020 Indigenous cohort (females 87.8%, males 83.0%) (Figure 5.1).

There was an increase in disparity of coverage in 2022 between those resident in the lowest socioeconomic quintile areas compared to those in the highest quintile. For the 2022 15 year old cohort, who turned 13 years in 2020 so would have been impacted by pandemic related school closures, this disparity was 3.8 percentage points in girls (was 1.2 in the 15 year old 2020 cohort) and 5.4 percentage points in boys (was 2.2 in the 15 year old 2020 cohort).  

Although coverage remained above 80% in all regions by sex there was an increasing disparity in coverage over time between very remote areas and other regions, notably affecting females in whom it exceeded 5% in 2022. Coverage remained above 80% in all jurisdictions in both sexes except in the NT where male coverage fell to 78.3% in males and 79.8% overall in 2022.  

Socioeconomic and regional disparities were similar in direction and magnitude amongst Indigenous adolescents as in the whole cohort. There was substantial variation in coverage by jurisdiction with coverage in females ranging from 74.6% in SA to 88.5% in the ACT and coverage in males ranging from 65.6% in SA to 82.7% in the ACT (Figure 5.2). In males coverage in 2022 was below 80% in all but two jurisdictions (ACT and NSW). In females coverage was below 80% in two jurisdictions (SA and NT). (Figure 5.2). Following progressive improvements in coverage and reductions in disparity between Indigenous and non-Indigenous adolescents between 2016 and 2020, coverage in all groups fell in 2021 and 2022 and disparities have re-emerged. (Figure 5.3)

Source: Australian Immunisation Register (AIR) data, as at 2nd April 2023 for 2022 data and as at 3rd April 2022 for 2021 data, sourced from NCIRS.

Updated data are for the 15-year-old cohort in 2021 and 2022 (i.e. those born 1 Jan 2006 - 31 Dec 2006 and 1 Jan 2007 - 31 Dec 2007) and only includes HPV vaccinations administered prior to 15th birthday. 

Australia’s both-sex vaccination program provides substantial protection to non-vaccinated women. Modelling has suggested, for countries that have introduced both-sex vaccination, that elimination of vaccine-preventable HPV types is likely achievable with a sustained coverage of 80% (5). In 2022, despite coverage declines since 2020, overall national coverage exceeded this threshold at 84.2%. However, through 2021 and 2022, inequity in coverage has increased by available demographic variables notably for Indigenous adolescents and by jurisdiction of residence, which will need to be addressed in order to achieve elimination equitably. It is to be hoped that these declines and growing inequities can be reversed in the post pandemic period as school programs return to normal and single dose vaccination creates the opportunity for easy catch up in multiple settings including in school, in primary care and in community settings such as pharmacies. Data are not yet available reporting coverage for other priority populations such as people who are part of culturally and linguistically diverse communities, those living with disability, or those who are medically at higher risk from HPV (eg immunosuppressed). 

It should be noted that this indicator is designed to monitor achievement of coverage by a certain age over time rather than highest coverage ever achieved in a birth cohort (for example by including doses delivered at age 15 or afterwards). Data suggests that coverage by birth cohort currently peaks at age 19 years (6). There is now an additional opportunity to improve coverage further, and mitigate the dilution of coverage by immigration in the young adult age group, through the extended funded single dose catch up introduced in 2023 through to age 25 years inclusive. 

1 World Health Organization. Global strategy to accelerate the elimination of cervical cancer as a public health problem. 2020. Available at: https://www.who.int/ publications/i/item/9789240014107. 

2 Simms KT, Steinberg J, Caruana M, et al. Impact of scaled up human papillomavirus vaccination and cervical screening and the potential for global elimination of cervical cancer in 181 countries, 2020-99: a modelling study. Lancet Oncology 2019; 20(3): 394-407. 

3 Bruni L, Saura-Lazaro A, Montoliu A, et al. HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019. Preventive Medicine 2020: 106399. 

4 Australian Centre for the Prevention of Cervical Cancer. National Strategy for the Elimination of Cervical Cancer in Australia. November 2023. Available at: https://www.health.gov.au/resources/publications/national-strategy-for-the-elimination-of-cervical-cancer-in-australia?language=en  

5 Brisson M, Benard E, Drolet M, et al. Population-level impact, herd immunity, and elimination after human papillomavirus vaccination: a systematic review and meta-analysis of predictions from transmission-dynamic models. Lancet Public Health 2016; 1(1): e8-e17. 

6 Hull B, Hendry A, Dey A, Brotherton J, Macartney K, Beard F. Annual immunisation coverage report 2022. National Centre for Immunisation Research and Surveillance 2023. Available online at: https://ncirs.org.au/sites/default/files/2024-01/NCIRS%20Annual%20immunisation%20coverage%20report%202022.pdf