Knowledge and Awareness of HPV, the HPV Vaccine and Cancer-Related HPV Types among Indigenous Australians
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1. Introduction
Human Papilloma Virus (HPV) infection is a common, preventable, sexually transmitted disease with an increasing incidence globally [1]. With an estimated incidence of 80% among women and men by 45-years-old, nearly all sexually active adults contract HPV during their lifetime, with the majority successfully clearing without clinical presentation [2,3]. The small, double-stranded DNA virus infects basal cells in the epithelium of the skin and mucous membranes, possibly leading to presentations such as warts and cancers of the cervix, oropharynx, anus, penis and vulva [4,5,6,7]. HPV can be transferred during sexual intercourse, oral sex, kissing, vaginal birth, autoinoculation and from fomites, where a person has been exposed to contaminated items for a prolonged period [4,8]. The number of sexual partners, age of sexual debut and sexual behaviors change the HPV infection risk [8,9]. Over 200 subtypes of HPV have been detected and categorized into high-risk (hr) and low-risk (lr) types [8]. HPV types 16 and 18 are within the high-risk group and most strongly associated with cancer, being detected in the majority of HPV-positive oral and oropharyngeal cancers (OPCs) and 70–80% of cervical cancers globally [4,5,6]. Previously, the most common HPV-driven cancers were cervical cancers, but these have been surpassed by OPCs, which involve the tonsillar area, base of tongue and soft palate [10,11,12]. The survival rates associated with HPV-positive OPCs appear to be better than non-HPV-related OPCs [6].
The HPV vaccine is effective against the two most common hr HPV types when administered prior to exposure [13]. Australia was the first country to fund a National HPV Vaccination Program, with delivery to girls starting in 2007 and boys in 2013. The school-based program delivers the vaccine to Year 7 adolescents (aged 12–13 years). Those who missed out can receive the vaccine for free up to 26 years old [14]. Initially, the vaccine program was a 3-dose quadrivalent Gardasil HPV vaccine, which was replaced with a 2-dose nonvalent HPV vaccine from 2018. Since February 2023, the program has adopted a single-dose system using a Gardasil®9 vaccination (effective against HPV types 6, 11, 16, 18, 31, 33, 45, 52 and 58) [15,16]. The national vaccination coverage for Indigenous Australian adolescents has been high, with 2016 data showing over 80% of girls and boys received at least 1 dose; however, course completion was low [15]. With the transition to single-dose administration, coverage is likely to improve.
Aboriginal and Torres Strait Islander people (hereby respectfully referred to as Indigenous Australians) have resided in the country for over 50,000 years and represent 3.3% of Australia’s population [5]. The connection to land, family, culture and spirit often contributes to overall well-being [5]. Many Indigenous cultures educate younger generations about history, country and health through storytelling. However, in the past, Indigenous groups were discouraged from discussing sexual health, making it difficult to share important information with children and grandchildren [17]. Globally, Indigenous people experience disproportionate health inequalities compared to non-Indigenous people, as well as the ongoing effects of colonization and systemic racism [18,19]. Despite efforts to close the health equity gap in Australia, Indigenous Australians experience higher incidence rates of cancer and have less chance of surviving five years after diagnosis compared to non-Indigenous Australians [20].
Generally, screening and vaccination have reduced the incidence of HPV infection; however, evidence shows that Indigenous Australians are still experiencing higher HPV infection rates [1,5]. In 2020, the Australian Research Centre for Public Oral Health (ARCPOH) reported that 35.5% of Indigenous Australian participants were positive for any oral HPV infection [5]. The prevalence was found to be 15 times that among young non-Indigenous Australians and 4.7 times that reported by Antonsson et al. in a systematic review of 9 international papers [5]. Multiple barriers to receiving the HPV vaccine among Indigenous groups have been found, impacting administration at its most effective time. These barriers include mistrust of health care systems, lacking understanding of HPV, resource constraints, service infrastructure gaps, staff shortages, sensitivity regarding sexual health promotion and concerns regarding medical practitioner abilities [17,21,22]. There is limited evidence regarding HPV-related OPCs or HPV vaccine uptake among Indigenous Australians [9].
It is well understood that lack of information contributes to vaccine reluctance, with many studies suggesting that increasing awareness of HPV, its vaccine and its association with cancer can contribute to better vaccine uptake and infection prevention [18,21,23,24,25,26,27]. A study involving American Indian adolescents found that HPV vaccine initiation was higher among those whose parents were aware of the vaccine and had received a recommendation from their medical practitioner for their child to receive it [28]. Researchers have suggested that Indigenous participants have “little” knowledge about HPV, its mode of transmission, the HPV vaccine or its oncogenic potential [28]. However, there was no evidence quantifying knowledge of HPV, its vaccine and related cancers among Indigenous Australians, or the individual factors associated with poorer knowledge.
This study aimed to gain an understanding of the knowledge and awareness of HPV, the HPV vaccine, and HPV-related cancers, and to evaluate the relationship between participant characteristics and knowledge of HPV, HPV vaccination uptake and cancer-related high-risk HPV (HPV16/18) infection, among Indigenous Australian adults. We hypothesized that Indigenous Australians have limited knowledge and awareness regarding HPV, the HPV vaccine, and HPV-related cancers, and that multiple factors contribute to this.
4. Discussion
The mean HPV-KT score was low (2.3), supporting the hypothesis that Indigenous Australians have limited knowledge and awareness regarding HPV, the HPV vaccine, and HPV-related cancers. Multiple contributing factors, such as education, health care card status, HPV infection, general health, sexual behavior and self-rated HPV knowledge, were identified.
All the HPV-KT questions, except question nine, had more “Don’t Know” responses than “True” and “False” combined. This highlights that many participants did not have incorrect knowledge but were rather unaware of HPV, its high occurrence, transmission, and oncogenic potential. The two lowest scoring questions were “HPV is very rare” and “HPV always has visible signs or symptoms”, indicating the need to improve education regarding the commonness of HPV and asymptomatic infection.
The total prevalence of HPV vaccination was 27%. Most national and international estimates focus on vaccination coverage among adolescents, making a comparison of the vaccination rate among Indigenous Australian adults difficult. The HPV vaccination rates were significantly higher among the younger age group, a result of the HPV vaccination program commencing in 2007. Until 2013, only females were provided with HPV vaccination in school, likely contributing to the difference in vaccination coverage among males and females. The vaccination rates were higher among those who had previously heard of and had some knowledge regarding HPV (35.5%), supporting the long-term idea that education facilitates vaccination.
The HPV 16 and/or 18 infection prevalence among the Indigenous Australian participants (4.7%) exceeded rates reported among young Australians (1.3%) and an international systematic review involving nine papers (average HPV 16 prevalence of 1.6%) [31,32].
Indigenous populations face multiple barriers when considering receiving the HPV vaccination. These barriers are a consistent trend, with Indigenous people in Canada, Aotearoa New Zealand, and the USA all reporting low awareness of the HPV vaccine and low access to culturally safe clinics [24]. When strategizing how to improve Indigenous population health, it is important to consider Indigenous health practices and methods of sharing information. International studies highlight that the development of culturally sensitive education strategies, based on the current reported barriers to and facilitators of vaccination, can encourage parents to make informed decisions about vaccinating their children [17,33]. Several strategies have been suggested, including collaboration with Indigenous communities to create educational programs that adopt a verbal approach, community-based vaccination programs, individual counselling, and increased health care provider knowledge and recommendations [17,22,33,34,35].
The strengths of this study include the engagement with Indigenous Australian communities through partnerships and involvement of the Indigenous Reference Group, a large sample size, and psychometric analysis of the 10-item HPV-KT prior to use. A study limitation was the cross-sectional design, preventing the testing of causal hypotheses. Psychometric analysis of the 7-item HPV-KT found poor reliability for the questions associated with “commonness of HPV”. Despite this, it was recommended for use among Indigenous Australians, with the use of a subscale listed as a limitation.
We hope that the findings of this project can be used by policy makers to allocate funding into culturally sensitive education strategies. A lack of knowledge has been found in our study; further research can be conducted to determine whether the lack of knowledge among Indigenous Australians is contributing to the higher HPV and HPV-related OPC incidence among this population.
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