Assessing HPV vaccine coverage in Australia by geography and socioeconomic status: are we protecting those most at risk?

Epidemiology of HPV-associated cancers past, present and future: towards prevention and elimination

Cervical cancer is the first cancer deemed amenable to elimination through prevention, and thus lessons from the epidemiology and prevention of this cancer type can provide information on strategies to manage other cancers. Infection with the human papillomavirus (HPV) causes virtually all cervical cancers, and an important proportion of oropharyngeal, anal and genital cancers. Whereas 20th century prevention efforts were dominated by cytology-based screening, the present and future of HPV-associated cancer prevention relies mostly on HPV vaccination and molecular screening tests. In this Review, we provide an overview of the epidemiology of HPV-associated cancers, their disease burden, how past and contemporary preventive interventions have shaped their incidence and mortality, and the potential for elimination. We particularly focus on the cofactors that could have the greatest effect on prevention efforts, such as parity and human immunodeficiency virus infection, as well as on social determinants of health. Given that the incidence of and mortality from HPV-associated cancers remain strongly associated with the socioeconomic status of individuals and the human development index of countries, elimination efforts are unlikely to succeed unless prevention efforts focus on health equity, with a commitment to both primary and secondary prevention.

Stakeholders' experiences with school-based immunization programs during the COVID-19 pandemic in the Canadian Maritimes: A qualitative study

Background

School-based immunization programs (SBIP) support access to routine vaccines for adolescents. Across Canada, the COVID-19 pandemic and subsequent public health measures affected SBIP and vaccine uptake. The objectives of this study were to explore 1.) stakeholders' experiences with SBIP and changes to programs during COVID-19 in Nova Scotia, Prince Edward Island and New Brunswick, and 2.) how the pandemic affected parents' and adolescents' vaccine views.

Study design

Semi-structured interviews with decision makers, healthcare providers, teachers, parents and adolescents between February-August 2023.

Methods

The COM-B model and Theoretical Domains Framework informed interview guides. Deductive and inductive analyses saw participant quotes mapped to relevant model components and domains by two coders. Belief statements were generated within each stakeholder group then compared to identify themes and subthemes.

Results

Participants (n = 39) identified five themes: 1) enablers to SBIP delivery, 2) barriers to SBIP delivery, 3) desired changes to SBIP delivery, 4) student anxiety, and 5) vaccination views and changes since the COVID-19 pandemic. Public health measures facilitated more space for clinics, as did taking smaller cohorts of students. School staff-healthcare provider relationships could help or hinder programs, particularly with high turnover in both professions during the pandemic. Adolescents played a passive role in vaccine decision making, with mothers often being the sole decision maker. We did not identify any changes in hesitancy towards routine vaccines since the pandemic.

Conclusions

We identified a range of barriers and enablers to SBIP, many of which were exacerbated by the pandemic. Efforts are needed to ensure SBIP and catch-up programming remains accessible for all adolescents to catch-up on missed vaccines before graduation. Parents and adolescents' vaccination views suggest changes in vaccine coverage since the pandemic may be due to accessibility of services rather than vaccine hesitancy. Future research is needed to engage adolescents in their vaccine decisions.

Pre-Vaccination Human Papillomavirus Genotypes and HPV16 Variants among Women Aged 25 Years or Less with Cervical Cancer

Background: In 2007, Australia introduced a national human papillomavirus (HPV) vaccination program. In 2017, the onset of cervical screening changed from 18 to 25 years of age, utilising human papillomavirus (HPV) nucleic acid testing. The objective of the study is to describe the HPV genotypes and HPV16 variants in biopsies from women ≤ 25 years of age with cervical carcinoma (CC) (cases), compared with those aged >25 years (controls), in a pre-vaccination cohort. Methods: HPV genotyping of archival paraffin blocks (n = 96) was performed using the INNO-LiPA HPV Genotyping assay. HPV16-positive samples were analysed for variants by type-specific PCR spanning L1, E2 and E6 regions. Results: HPV16 was the commonest genotype in cases (54.5%, 12/22) and controls (66.7%, 46/69) (p = 0.30), followed by HPV18 (36.3%, 8/22 vs. 17.3% 12/69, respectively) (p = 0.08). Furthermore, 90% (20/22) of cases and 84.1% (58/69) of controls were positive for HPV16 or 18 (p = 0.42); 100% (22/22) of cases and 95.7% (66/69) of controls had at least one genotype targeted by the nonavalent vaccine (p = 0.3). The majority of HPV16 variants (87.3%, 48/55) were of European lineage. The proportion of unique nucleotide substitutions was significantly higher in cases (83.3%, 10/12) compared with controls (34.1%, 15/44), (p < 0.003, χ2, OR 9.7, 95%CI 1.7–97.7). Conclusions: Virological factors may account for the differences in CCs observed in younger compared with older women. All CCs in young women in this study had preventable 9vHPV types, which is important messaging for health provider adherence to new cervical screening guidelines.

Disparities in Human Papillomavirus vaccination coverage among adolescents in Australia: A geospatial analysis

AIM

This ecological study aimed to examine the geographic patterns in Human Papillomavirus (HPV) vaccination rates among boys and girls aged 15 years across locations in Australia, in addition to assessing contextual area-level factors that may explain the variations in HPV vaccination coverage.

METHODS

Aggregate HPV vaccination data for Australian girls and boys aged 15 years from 2015 to 16 was obtained from the Australian Institute of Health and Welfare for each Statistical Area level 4 (SA4). A Gradient Boosting Machine learning model was applied to assess the predictors' importance for the study outcomes. Geographically weighted regression (GWR) models were run to assess whether substantially different relationships between predictors and outcomes occur at different locations in space.

RESULTS

Completed HPV vaccination across the 88 SA4 regions ranged from 57.6% to 90.6% among girls, and from 53.6% to 85.5% among boys. The 2016 SEIFA Index of Economic Resources was the variable with the highest contribution to the predictions of both girls' and boys' HPV vaccination rates. Selected predictors explained 45% and 72% of the geographic variance in vaccination rates among boys and girls, respectively. Normalised coefficients for both GWR models showed a high variation in the associations between predictors and HPV vaccination rates across regions.

CONCLUSION

Socioeconomic and education factors were important predictors for HPV vaccination rates among Australian boys and girls aged 15 years, although no variable presented a uniform effect on HPV vaccination across SA4 regions. Important spatial heterogeneity in the effect of predictors was identified across the study area.

Measuring school level attributable risk to support school-based HPV vaccination programs

Background

In Australia in 2017, 89% of 15-year-old females and 86% of 15-year-old males had received at least one dose of the HPV vaccine. However, considerable variation in HPV vaccination initiation (dose one) across schools remains. It is important to understand the school-level characteristics most strongly associated with low initiation and their contribution to the overall between-school variation.

Methods

A population-based ecological analysis was conducted using school-level data for 2016 on all adolescent students eligible for HPV vaccination in three Australian jurisdictions. We conducted logistic regression to determine school-level factors associated with lower HPV vaccination initiation (< 75% dose 1 uptake) and estimated the population attributable risk (PAR) and the proportion of schools with the factor (school-level prevalence).

Results

The factors most strongly associated with lower initiation, and their prevalence were; small schools (OR = 9.3, 95%CI = 6.1–14.1; 33% of schools), special education schools (OR = 5.6,95%CI = 3.7–8.5; 8% of schools), higher Indigenous enrolments (OR = 2.7,95% CI:1.9–3.7; 31% of schools), lower attendance rates (OR = 2.6,95%CI = 1.7–3.7; 35% of schools), remote location (OR = 2.6,95%CI = 1.6–4.3; 6% of schools,) and lower socioeconomic area (OR = 1.8,95% CI = 1.3–2.5; 33% of schools). The highest PARs were small schools (PAR = 79%, 95%CI:76–82), higher Indigenous enrolments (PAR = 38%, 95%CI: 31–44) and lower attendance rate (PAR = 37%, 95%CI: 29–46).

Conclusion

This analysis suggests that initiatives to support schools that are smaller, with a higher proportion of Indigenous adolescents and lower attendance rates may contribute most to reducing the variation of HPV vaccination uptake observed at a school-level in these jurisdictions. Estimating population-level coverage at the school-level is useful to guide policy and prioritise resourcing to support school-based vaccination programs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13088-x.

HPV vaccination coverage: slightly improved two-dose schedule completion estimates and historical estimates lower on AIR than HPV Register

OBJECTIVE

To compare Australian Immunisation Register (AIR) human papillomavirus (HPV) vaccination coverage against historical data from the former National HPV Vaccination Program Register and estimate two-dose vaccination coverage.

METHODS

Cross-sectional analysis of registry data for adolescent birth cohorts (1998-2007). Denominator populations were Medicare enrolments (AIR) and ABS estimated resident populations (HPV register).

RESULTS

For adolescents aged <17 years, AIR coverage estimates were several percentage points lower than HPV register estimates due to a larger Medicare enrolment denominator. Completed course coverage (two or three valid doses) for 15-year-old females in 2020 was 81.5% and for males 78.6%, higher than completed course coverage in 15-year-olds in 2019 (79.7 and 76.8% respectively). First dose coverage was similar for Indigenous adolescents but course completion was lower, although improving over time. Course completion was slightly lower (3.5-5.7%) in areas of lowest socioeconomic status and greatest remoteness.

CONCLUSIONS

Coverage is slightly lower using AIR than HPV register estimates. Moving from three to two doses has slightly improved completion, likely due to the wider dose spacing, but equity gaps remain.

IMPLICATIONS FOR PUBLIC HEALTH

An ongoing focus on equity in vaccine delivery is needed. Systems, reminders and catch-up opportunities to ensure course completion remain important.

Differences in school factors associated with adolescent HPV vaccination initiation and completion coverage in three Australian states

BACKGROUND

Schools are the primary setting for the delivery of adolescent HPV vaccination in Australia. Although this strategy has achieved generally high vaccination coverage, gaps persist for reasons that are mostly unknown. This study sought to identify school-level correlates of low vaccination course initiation and completion in New South Wales, Tasmania, and Western Australia to inform initiatives to increase uptake.

METHODS

Initiation was defined as the number of first doses given in a school in 2016 divided by vaccine-eligible student enrolments. Completion was the number of third doses given in a school in 2015-2016 divided by the number of first doses. Low initiation and completion were defined as coverage ≤ 25thpercentile of all reporting schools. We investigated correlations between covariates using Spearman's rank correlation coefficients. Due to multicollinearity, we used univariable logistic regression to investigate associations between school characteristics and low coverage.

RESULTS

Median initiation was 84.7% (IQR: 75.0%-90.4%) across 1,286 schools and median completion was 93.8% (IQR: 86.0%-97.3%) across 1,295 schools. There were strong correlations between a number of school characteristics, particularly higher Indigenous student enrolments and lower attendance, increasing remoteness, higher postcode socioeconomic disadvantage, and smaller school size. Characteristics most strongly associated with low initiation in univariate analyses were small school size, location in Tasmania, and schools catering for special educational needs. Low completion was most strongly associated with schools in Tasmania and Western Australia, remote location, small size, high proportion of Indigenous student enrolments, and low attendance rates.

CONCLUSION

This study provides indicative evidence that characteristics of schools and school populations are associated with the likelihood of low initiation and completion of the HPV vaccination course. The findings will guide further research and help target initiatives to improve vaccination uptake in schools with profiles associated with lower coverage.

Achieving cervical cancer elimination among Indigenous women

Achieving the World Health Organisation (WHO) cervical cancer elimination target of fewer than four new cases per 100,000 woman-years requires scaling up HPV vaccination of girls, cervical screening, and pre-cancer and cancer treatment. We reviewed data from four high-income colonised countries (Australia, Canada, Aotearoa New Zealand (NZ), and the United States (US)) to identify how each is currently performing compared to the cervical cancer incidence elimination and triple-intervention targets, nationally and in Indigenous women. We also summarise barriers and enablers to meeting targets for Indigenous women. To achieve elimination, cervical cancer incidence must be reduced by 74% in Indigenous women in Australia, and 63% in Maori women in NZ; data were not published in sufficient detail to compare incidence in Indigenous women in Canada or the US to the WHO target. Only Australia meets the vaccination coverage target, but uptake appears comparatively equitable within Australia, NZ and the US, whereas there appears to be a substantial gap in Canada. Screening coverage is lower for Indigenous women in all four countries though the differential varies by country. Currently, only Australia universally offers HPV-based screening. Data on pre-cancer and cancer treatment were limited in all countries. Large inequities in cervical cancer currently exist for Indigenous peoples in Australia, Canada, New Zealand and the US, and elimination is not on track for all women in these countries. Current data gaps hinder improvements. These countries must urgently address their systemic failure to care and provide health care for Indigenous women.

The impact of socioeconomic status on HPV infection among young Brazilians in a nationwide multicenter study

The aim of this study is to evaluate genital human papillomavirus (HPV) infection according to socioeconomic categories in Brazil. This cross-sectional, nationwide study included 7,694 sexually active women and men aged 16-25 years. Individuals of all socioeconomic groups in all 26 Brazilian capitals and the Federal District were enrolled through public primary care units between September 2016 and November 2017. All participants answered a standardized interview administered by trained primary care health professionals. Socioeconomic class was analyzed using a pricing classification system for the Brazilian public that divides the market exclusively in terms of economic class based on the ownership of assets and the education level. Cervical samples were obtained using a Digene® HC2 DNA Collection, and penile/scrotum samples were obtained using a wet Dacron swab. HPV typing (overall and high-risk) was performed in a central lab. Of the 7,694 participants (47.85% women), 17.92% belonged to class A-B, 56.08% to class C, and 26.00% to class D-E. The prevalence of overall HPV was similar among the social classes: 51.16% for classes A-B, 53.39% for class C, and 55.47% for classes D-E (P = 0.479). Similar results were found for high-risk HPV. After adjustments, the presence of HPV in individuals with a brown skin color belonging to classes A-B was 57.00% higher [prevalence ratio 1.57 (95%: 1.23, 2.01)] than that in whites and had no impact on the other social classes. In conclusion, HPV infection affects all socioeconomic classes in Brazil, evidencing the importance of offering the HPV vaccine to the entire population.

Countering vaccine hesitancy through immunization information systems, a narrative review

Immunization is one of the most important public health interventions to contrast infectious disease; however, many people nowadays refuse vaccination. Vaccine hesitancy (VH) is due to several factors that influence the complex decision-making process. Information technology tools might play an important role in vaccination programs. In particular, immunization information systems (IISs) have the potential to improve performance of vaccination programs and to increase vaccine uptake. This review aimed to present IIS functionalities in order to counter VH. In detail, we analyzed the automatic reminder/recall system, the interoperability of the system, the decision support system, the web page interface and the possibility to record adverse events following immunization. IIS could concretely represent a valid instrument to increase vaccine confidence, especially trust in both health-care workers and decision makers. There are not enough trials aimed to evaluate the efficacy of IIS to counter VH. Further researches might focalize on this aspect.

HPV vaccine coverage in Australia and associations with HPV vaccine information exposure among Australian Twitter users

Introduction: Human papillomavirus (HPV) vaccine coverage in Australia is 80% for females and 76% for males. Attitudes may influence coverage but surveys measuring attitudes are resource-intensive. The aim of this study was to determine whether Twitter-derived estimates of HPV vaccine information exposure were associated with differences in coverage across regions in Australia.

Methods: Regional differences in information exposure were estimated from 1,103,448 Australian Twitter users and 655,690 HPV vaccine related tweets posted between 6 September 2013 and 1 September 2017. Tweets about HPV vaccines were grouped using topic modelling; an algorithm for clustering text-based data. Proportional exposure to topics across 25 regions in Australia were used as factors to model HPV vaccine coverage in females and males, and compared to models using employment and education as factors.

Results: Models using topic exposure measures were more closely correlated with HPV vaccine coverage (female: Pearson’s R = 0.75 [0.49 to 0.88]; male: R = 0.76 [0.51 to 0.89]) than models using employment and education as factors (female: 0.39 [−0.02 to 0.68]; male: 0.36 [−0.04 to 0.66]). In Australia, positively-framed news tended to reach more Twitter users overall, but vaccine-critical information made up higher proportions of exposures among Twitter users in low coverage regions, where distorted characterisations of safety research and vaccine-critical blogs were popular.

Conclusions: Twitter-derived models of information exposure were correlated with HPV vaccine coverage in Australia. Topic exposure measures may be useful for providing timely and localised reports of the information people access and share to inform the design of targeted vaccine promotion interventions.

Trends in anogenital wart incidence among Tennessee Medicaid enrollees, 2006-2014: The impact of human papillomavirus vaccination

Introduction

Evidence of human papillomavirus (HPV) vaccine impact on anogenital warts (AGWs) by race or urbanicity in the US is lacking. We evaluated HPV vaccine impact in Tennessee by assessing AGW trends among Tennessee Medicaid (TennCare) enrollees aged 15–39 years from 2006-2014.

Methods

Persons with incident AGWs were identified using diagnosis/pharmacy codes from TennCare billing claims. We calculated sex-specific annual AGW incidence by age group, race, and urbanicity; estimated annual percent changes (APCs) using log-linear models; and performed pairwise comparisons by race and urbanicity.

Results

AGW incidence decreased among females aged 15–19 (APC = −10.6; P < 0.01) and 20–24 years (APC = −3.9; P = 0.02). Overall trends were similar between Whites and Blacks, and between those living in metropolitan statistical areas (MSAs) and non-MSAs. Rates among males aged 15–19 years began decreasing after 2010. Among enrollees aged 25–39 years, rates increased or were stable.

Conclusions

Following introduction of the HPV vaccine in 2006, AGWs decreased among age groups most likely to be vaccinated. The change in trend among young males after 2010 suggests early herd effects. Our findings indicate vaccine effects and support the importance of improving adherence to current vaccination recommendations for preventing AGWs and other HPV-related diseases.

Human Papillomavirus and Oropharyngeal Cancer Among Indigenous Australians: Protocol for a Prevalence Study of Oral-Related Human Papillomavirus and Cost-Effectiveness of Prevention

Background

Oropharyngeal cancer is an important, understudied cancer affecting Aboriginal and Torres Strait Islander Australians. The human papillomavirus (HPV) is a significant risk factor for oropharyngeal cancer. Current generation HPV vaccines are effective against the 2 most common types of high-risk HPVs in cancer (hrHPVs 16/18).

Objectives

This study aims (1) to yield population estimates of oncogenic genotypes of HPV in the mouth and oropharynx of defined Aboriginal and Torres Strait Islander populations; (2) to estimate the proportion of oropharyngeal cancer attributable to HPV among these Australian citizens; (3) to estimate the impact of HPV vaccination as currently implemented on rates of oropharyngeal cancer among Aboriginal and Torres Strait Islander Australians; and (4) taking into account impact on oropharyngeal as well as cervical cancer, to evaluate efficacy and cost-effectiveness of targeted extended HPV vaccination to older ages, among our study population.

Methods

Our study design and operation is straightforward, with minimal impost on participants. It involves testing for carriage of hrHPV in the mouth and oropharynx among 1000 Aboriginal South Australians by simple saliva collection and with follow-up at 12 and 24 months, collection of sexual history at baseline, collection of information for estimating health state (quality-of-life) utilities at baseline, genotyping of viruses, predictive outcome and cost-effectiveness modeling, data interpretation and development of vaccination, and follow-up management strategies driven by the Aboriginal community.

Results

Participant recruitment for this study commenced in February 2018 and enrollment is ongoing. The first results are expected to be submitted for publication in 2019.

Conclusions

The project will have a number of important outcomes. Synthesis of evidence will enable generation of estimates of the burden of oropharyngeal cancer among Aboriginal and Torres Strait Islander Australians and indicate the likely effectiveness and cost-effectiveness of prevention. This will be important for health services planning, and for Aboriginal health worker and patient education. The results will also point to important areas where research efforts should be focused to improve outcomes in Aboriginal and Torres Strait Islander Australians with oropharyngeal cancer. There will be a strong focus on community engagement and accounting for the preferences of individuals and the community in control of HPV-related cancers. The project has international relevance in that it will be the first to systematically evaluate prevention of both cervical and oropharyngeal cancer in a high-risk Indigenous population taking into account all population, testing, and surveillance options.

Registered Report Identifier

RR1-10.2196/10503

Decline in prevalence of human papillomavirus infection following vaccination among Australian Indigenous women, a population at higher risk of cervical cancer: The VIP-I study

BACKGROUND

Cervical cancer occurrence and mortality are strongly correlated with socioeconomic disadvantage, largely due to unequal access to screening and treatment. Universal human papillomavirus (HPV) vaccination provides the opportunity to greatly reduce this global health disparity. Australian Indigenous women have substantially higher rates of cervical cancer than non-Indigenous women, primarily due to under-screening. We investigated HPV infection rates in Indigenous women 7 years after implementation of the national HPV vaccination program.

METHODS

We used a repeat cross-sectional design, with the baseline being provided by an HPV prevalence survey among Indigenous women attending clinics for cervical cytology screening, prior to the start of the vaccination program in 2007. We returned to clinics in four locations during 2014-15, and invited women aged 18-26 years attending for screening to provide a cervical specimen for HPV testing, as well as to complete a short questionnaire and consent to allow access of their records in the National HPV Vaccination Program Register. We used well-established laboratory methods to test specimens for specific HPV genotypes.

RESULTS

A total of 142 women were recruited at participating sites and compared to 155 who had been recruited at the same locations in the 2007 pre-vaccine survey. The two groups were identical in regard to age, with the more recent group having a higher proportion of hormonal contraception users, and a lower proportion of smokers. The proportion found to have any HPV type fell from 58 to 36% with the decline being entirely due to reductions in vaccine types, which fell by 94% from 24 to 1.4%.

CONCLUSION

Australia's national HPV vaccination program appears to be successfully protecting a very high proportion of Indigenous women against vaccine targeted HPV types, who have in the past been at elevated risk of cervical cancer.

Findings and Outcomes in a Prevaccination Cohort of Women Younger Than 25 Years Attending a Tertiary Colposcopy Service

OBJECTIVE

To describe clinical presentation and treatment in women younger than 25 years referred to the Royal Women's Hospital colposcopy clinic, before implementation of the National Human Papillomavirus Vaccination Program.

METHODS

Retrospective cohort analysis of women younger than 25 years referred to a tertiary hospital colposcopy clinic between 1998 and 2007. Clinical presentation and correlation between cervical cytology, biopsy, and histology at treatment was examined.

RESULTS

Approximately 14,635 colposcopies were undertaken in 4104 women (median age, 22 years); 3051 had abnormal referral cytology, of whom, 23.8% had high-grade disease on punch biopsy. High-grade disease was found in 15.1% of those with possible low-grade or low-grade cytology (293/1932), 42.4% of those with possible high-grade or high-grade cytology (474/1119). Sensitivity and specificity of colposcopy for high-grade disease (high-grade epithelial abnormality, adenocarcinoma in situ, cervical cancer up to 2 years follow-up) was 60.0% and 82.3%, respectively. Thirty-nine percent (n = 1180) with abnormal cytology had treatment, of which, 66.6% was ablative. Histological CIN3+ was found in 53.8% of those with a previous high-grade punch biopsy (126/234) at excisional treatment, and 23.0% of those with a previous low-grade punch biopsy (20/87) (relative risk, 2.3 [CI, 1.6-3.5]). Four cancers were detected (0.1% of the total cohort, 0.5% of those with a high-grade biopsy, and 1.7% of those with a high-grade biopsy who underwent excisional treatment.)

CONCLUSIONS

Before vaccination, young women experienced a high real-time burden of high-grade disease and high rates of intervention. These baseline data contribute to monitoring of HPV vaccination and revised cervical screening strategies.

Interventions to reduce inequalities in vaccine uptake in children and adolescents aged <19 years: a systematic review

BACKGROUND

In high-income countries, substantial differences exist in vaccine uptake relating to socioeconomic status, gender, ethnic group, geographic location and religious belief. This paper updates a 2009 systematic review on effective interventions to decrease vaccine uptake inequalities in light of new technologies applied to vaccination and new vaccine programmes (eg, human papillomavirus in adolescents).

METHODS

We searched MEDLINE, Embase, ASSIA, The Campbell Collaboration, CINAHL, The Cochrane Database of Systematic Reviews, Eppi Centre, Eric and PsychINFO for intervention, cohort or ecological studies conducted at primary/community care level in children and young people from birth to 19 years in OECD countries, with vaccine uptake or coverage as outcomes, published between 2008 and 2015.

RESULTS

The 41 included studies evaluated complex multicomponent interventions (n=16), reminder/recall systems (n=18), outreach programmes (n=3) or computer-based interventions (n=2). Complex, locally designed interventions demonstrated the best evidence for effectiveness in reducing inequalities in deprived, urban, ethnically diverse communities. There is some evidence that postal and telephone reminders are effective, however, evidence remains mixed for text-message reminders, although these may be more effective in adolescents. Interventions that escalated in intensity appeared particularly effective. Computer-based interventions were not effective. Few studies targeted an inequality specifically, although several reported differential effects by the ethnic group.

CONCLUSIONS

Locally designed, multicomponent interventions should be used in urban, ethnically diverse, deprived populations. Some evidence is emerging for text-message reminders, particularly in adolescents. Further research should be conducted in the UK and Europe with a focus on reducing specific inequalities.

The Association Between Unwanted Sexual Experiences and Early-Onset Cervical Cancer and Precancer by Age 25: A Case-Control Study

BACKGROUND

We examined the association between unwanted sexual experiences and cervical cancer, cervical intraepithelial neoplasia 3, adenocarcinoma in situ, diagnosed ≤25 years of age.

METHODS

A case-control study of women ≤55 years who attended gynecological hospitals in Australia between 1983 and 2007. Cases were ≤25 years when diagnosed with disease, control group 1 were "older women" >25 years at diagnosis; control group 2 were "well women" ≤25 years attending preventive health clinics. A self-administered postal survey was utilized. The main outcome measures were prevalence of childhood sexual abuse (<16 years) and unwanted adolescent sexual experiences (between 16 and 18 years) in cases compared to controls.

RESULTS

Of 400 contactable subjects, 251 participated (62.8%). Prevalence of childhood sexual abuse in cases (26.6% [25/94]) was similar to other groups. Prevalence of childhood genital contact abuse in cases with cervical cancer was 45.5% [5/11], compared to older women (20% [10/50], p = 0.08) and well women (13.8% [8/58], p = 0.01), and was marginally more common compared to well women when adjusted for other lifestyle factors (odds ratio [OR]: 4.7 [1.0-22.6], p = 0.05). Prevalence of unwanted adolescent sexual experiences in cases was 28.9% [33/114]. Prevalence of adolescent penile-genital contact experiences in cervical cancer cases was 46.7% [7/15], compared to older women (9.4%, [6/64], p < 0.001) and well women (13.7%, [10/73], p = 0.003), and was more common compared to well women when adjusted for lifestyle (OR: 5.9 [1.4-24.9], p = 0.02) and sexual health risk factors (OR: 5.6 [1.4-22.1] p = 0.01).

CONCLUSIONS

Unwanted sexual experiences with genital contact were a risk factor for invasive cervical cancer ≤25 years, likely due to a complex interplay of biological and environmental factors.

Attitudes, Knowledge and Factors Associated with Human Papillomavirus (HPV) Vaccine Uptake in Adolescent Girls and Young Women in Victoria, Australia

BACKGROUND

Human papillomavirus (HPV) vaccination targets high-risk HPV16/18 that cause 70% of all cancers of the cervix. In Australia there is a fully-funded, school-based National HPV Vaccination Program which has achieved vaccine initiation rate of 82% among age-eligible females. Improving HPV vaccination rates is important in the prevention of morbidity and mortality associated with HPV-related disease. This study aimed to identify factors and barriers associated with uptake of the HPV vaccine in the Australian Program.

METHODS

Between 2011 and 2014, females aged 18-25 years, living in Victoria, Australia who were offered HPV vaccination between 2007 and 2009 as part of the National HPV Vaccination Program, living in Victoria, Australia were recruited into a a young women's study examining effectiveness of the Australian National HPV Vaccination Program. Overall, 668 participants completed the recruitment survey, which collected data of participants' demographics and HPV knowledge. In 2015 these participants were invited to complete an additional supplementary survey on parental demographics and attitudes towards vaccinations.

RESULTS

In 2015, 417 participants completed the supplementary survey (62% response rate). Overall, 19% of participants were unvaccinated. In multivariate analyses, HPV vaccination was significantly associated with their being born in Australia (p<0.001), having completed childhood vaccinations (p<0.001) and their parents being main decision-makers for participants' HPV vaccination (p<0.001). The main reason reported for HPV non-vaccination was parental concern about vaccine safety (43%). Compared with HPV-vaccinated participants, those unvaccinated were significantly more likely to be opposed to all vaccines, including HPV vaccines (p<0.001) and were less likely to consider vaccinating their own children with all vaccines (p = 0.033), including HPV vaccines (p<0.001). Overall, 61% of unvaccinated participants reported that a recommendation from GPs would increase HPV vaccine acceptance.

CONCLUSIONS

Attitudes towards general health, vaccinations in general, as well as HPV vaccines are important in HPV vaccine uptake. Long-term monitoring of the knowledge, attitude and beliefs towards HPV vaccination in the community is critical to ensure a continued high uptake of the vaccine and success of the program.

Is HPV vaccination in pregnancy safe?

Millions of doses of HPV vaccine have been administered globally. Inadvertent administration of HPV vaccine during pregnancy occurs given that the main recipients of the vaccine are fertile young women, who might be unaware of their pregnancy at the time of their vaccination. To investigate the subject of HPV vaccine and pregnancy , the databases of PubMed and Embase were searched to find the relevant literature published in English within the last 10 y. Most of the evidence pertaining to fetal adverse events following HPV vaccination relates to spontaneous miscarriage. None of the relevant studies found any significantly increased rate of spontaneous abortion in the overall analyses. There was no indication of other HPV vaccine-associated adverse events in pregnancy or immediately post-conception.

Quadrivalent vaccine-targeted human papillomavirus genotypes in heterosexual men after the Australian female human papillomavirus vaccination programme: a retrospective observational study

BACKGROUND

Australia introduced a national quadrivalent human papillomavirus (4vHPV) vaccination programme for girls and young women in April, 2007. The HPV genotypes targeted by the female vaccine could also affect the protection afforded to heterosexual men. We examined the prevalence of 4vHPV targeted vaccine genotypes and the nine-valent HPV (9vHPV)-targeted vaccines genotypes among sexually active, predominantly unvaccinated heterosexual men from 2004 to 2015.

METHODS

We did a retrospective, observational study of urine and urethral swab specimens from heterosexual men aged 25 years or younger attending the Melbourne Sexual Health Centre between July 1, 2004, and June 30, 2015, who tested positive for Chlamydia trachomatis. We extracted HPV DNA and used the PapType HPV assay to detect 14 high-risk HPV genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) and two low-risk genotypes (6 and 11). We calculated the prevalence of any HPV genotype, genotypes 6 or 11, genotypes 16 or 18, genotypes in the 4vHPV group (6, 11, 16, or 18), five additional genotypes in the 9vHPV group (31, 33, 45, 52, or 58), and non-vaccine-targeted genotypes (31, 33, 35, 39, 45, 51, 56, 58, 59, 66, or 68).

FINDINGS

We obtained data between July 1, 2004, and June 30, 2015, and did the data analysis in December, 2015. Of 1764 specimens obtained, we included 1466 in our final analysis (the others were excluded because they had indeterminate results or were duplicates). The prevalence of any HPV genotype and genotypes 31, 33, 45, 52, and 58 did not change from 2004-05 to 2014-15, but we noted reductions in genotypes 6 and 11 (from 12% [95% CI 6-21%], to 3% [1-7%], p_trend=0·008), 16 and 18 (from 13% [95% CI 7-22%] to 3% [1-6%], p_trend<0·0001), and 4vHPV-targeted genotypes (from 22% [95% CI 14-33%] to 6% [3-10%], p_trend<0·0001). Prevalence of non-vaccine-targeted genotypes increased from 16% [95% CI 9-26%] to 22% [17-29%], p_trend<0·0001). In Australian-born men, 4vHPV-targeted genotype prevalence decreased from 11 of 55 [20%, 95% CI 10-33%] to two of 74 [3%, 0-11%], p_trend<0·0001); an even greater decline occurred in Australian-born men aged 21 years or younger (from four of 13 [31%, 95% CI 9-61%] to none of 25; p_trend<0·0001). Genotypes 16 and 18 decreased (adjusted prevalence ratio [PR] 0·32, 95% CI 0·14-0·74; p=0·008) but not genotypes 6 and 11 (adjusted PR 0·50, 0·16-1·56; p=0·234) in the postvaccination period among men who had arrived in Australia within 2 years from countries with a bivalent vaccine (2vHPV) programme (England, Scotland, Wales, Cook Islands, Northern Ireland, or the Netherlands), compared with the prevaccination period. No change was noted in 4vHPV genotypes in men born overseas in other countries.

INTERPRETATION

The marked reduction in prevalence of 4vHPV genotypes among mainly unvaccinated Australian-born men suggests herd protection has occurred from the female vaccination programme. Additionally, the decline in genotypes 16 and 18, but not genotypes 6 and 11, among overseas-born men predominantly from countries with a 2vHPV vaccine programme suggests that these men received benefits from herd protection for genotypes 16 and 18 from their vaccinated female partners in their own countries. These reductions could translate to reductions in HPV-related malignant conditions in men, even in countries with female-only vaccination programmes.

FUNDING

The Australian National Health and Medical Research Council Program.

Assortative sexual mixing among heterosexuals in Australia: implications for herd protection in males from a female human papillomavirus vaccination program

The aim was to investigate the assortative sexual mixing by country of birth among heterosexuals in Australia. An analysis of 1060 heterosexual couples who attended the Melbourne Sexual Health Centre between 2011 and 2014 was conducted. Of the 1060 couples, 27% (n = 281) were both Australian-born men and women, and 42% (n = 445) were both overseas-born. Of the 171 couples with women aged ≤21 years, 41% (n = 70) were both born in Australia and 33% (n = 56) were both born overseas. A strong assortative mixing pattern by country of birth was observed among all 1060 couples (r = 0.361; 95% CI: 0.320-0.403), and among 171 couples with women aged ≤21 years (r = 0.481; 95% CI: 0.379-0.584).

Trends in genital warts by socioeconomic status after the introduction of the national HPV vaccination program in Australia: analysis of national hospital data

BACKGROUND

Human papillomavirus (HPV) vaccination targeting females 12-13 years commenced in Australia in 2007, with catch-up of females 13-26 years until the end of 2009. No analyses of HPV vaccination program impact by either socioeconomic or geographic factors have been reported for Australia.

METHODS

Hospital admissions between July 2004-June 2011 involving a diagnosis of genital warts were obtained from a comprehensive national database. We compared sex- and age-specific admission rates in July 2006-June 2007 (pre-vaccination period) and July 2010-June 2011 (post-vaccination period) according to Index of Relative Socio-economic Disadvantage, nationally and stratified by remoteness area relating to the individual's area of residence, using Poisson/ negative binomial models.

RESULTS

Admission rates per 100,000 population in females aged 10-19 years (predominantly vaccinated at school), reduced from 42.2 to 6.0 (rate reduction 86.7 %; 95 % CI:82.2-90.0 %) in more disadvantaged areas and from 26.8 to 4.0 (85.0 %; 95 % CI:79.7-88.9 %) in less disadvantaged areas. In females aged 20-29 years (predominantly vaccinated in the community), the decreases were from 73.9 to 26.4 (66.0 %; 95 % CI:57.7-72.6 %) and from 61.9 to 23.8 (61.6 %; 95 % CI:52.9-68.7 %) in more and less disadvantaged areas, respectively. The reductions were similar in more vs less disadvantaged areas both inside major cities (88.6 %; 95 % CI: 82.2-92.7 % vs 87.9 %; 95 % CI:82.6-91.6 % in females aged 10-19 years; 64.0 %; 95 % CI:57.0-69.9 % vs 63.8 %; 95 % CI:52.9-72.1 % for females aged 20-29 years) and outside major cities (88.8 %; 95 % CI: 83.7-92.3 % vs 85.8 %; 95 % CI:73.5-92.4 % in females aged 10-19 years; 71.1 %; 95 % CI:58.8-79.7 % vs 67.6 %; 95 % CI:48.2-79.8 % for females aged 20-29 years). Admission rates in males aged 20-29 years also reduced, by 23.0 % (95 % CI:4.8-37.8 %) and 39.4 % (95 % CI:28.9-48.3 %) in more versus less disadvantaged areas respectively.

CONCLUSIONS

The relative reduction in genital warts appears similar in young females across different levels of disadvantage, including within and outside major cities, both for females predominantly vaccinated at school and in the community.

Effectiveness of less than three doses of quadrivalent human papillomavirus vaccine against cervical intraepithelial neoplasia when administered using a standard dose spacing schedule: Observational cohort of young women in Australia

Background

Optimised two-dose human papillomavirus (HPV) vaccine schedules are now endorsed for young adolescents by the World Health Organization. Limited data are available about effectiveness of <3 doses using a standard dose schedule.

Methods

Deterministic data linkage was undertaken between the Victorian Cervical Cytology Registry and National HPV Vaccination Program Register to determine quadrivalent HPV vaccination status and incidence of cervical pathology among vaccine eligible women (aged 26 years or younger in 2007) screened in Victoria, Australia between April 2007 and December 2011. Proportional hazards regression was used to estimate hazard ratios (HR) adjusted for age, socioeconomic status and area of residence. Women were stratified into those vaccinated before or after first screen.

Results

Any number of doses (1, 2 or 3) were associated with lower rates of high grade and low grade cytology diagnoses as long as doses were given before screening commencement (one dose HR high grade 0.44 (95% CI 0.32–0.59), one dose low grade 0.48 (95% CI 0.40–0.58); two doses HR high grade 0.63 (95% CI 0.50–0.80), HR low grade 0.52 (95% CI 0.44–0.61); three doses HR high grade 0.53 (95% CI 0.47–0.60), HR low grade 0.73 (95% CI 0.68–0.78)). Three doses of vaccine, but not fewer, were associated with reduced risk of high grade histologically confirmed abnormality in this cohort, regardless of whether vaccination occurred before or after screening (HR before 0.71 (95% CI 0.64–0.80), HR after 0.87 (95% CI 0.82–0.93)). Secondary analyses censoring end points occurring within 1, 6, 12, or 24 months of final vaccine dose suggested an increasing effect of partial vaccination courses over time.

Conclusion

Our data suggest that less than three doses of quadrivalent HPV vaccine provides some protection against cervical intraepithelial neoplasia, even when measured within 5 years in a population including those who were sexually active at the time of vaccination.

Cervical cancer prevention in Australia: Planning for the future

The high rate of coverage that has been achieved to date by the Australian government's Human Papillomavirus (HPV) Vaccination Program has already led to profound reductions in the prevalence of biopsy-confirmed, high-grade abnormalities and of vaccine-preventable HPV types in Australia. Declines in the prevalence of vaccine preventable HPV have occurred not only in vaccinated women but also in unvaccinated women, suggesting a herd-immunity affect. These declines were anticipated on the basis of modelling and were the major drivers for the changes proposed to the Australian National Cervical Screening Program. The federal and state-based Australian governments established a "Renewal Steering Committee," which conducted a literature search and a review of the available evidence to assess its applicability and quality. Together with this information the committee also used modeling to determine the optimal screening pathway for cervical cancer screening and constructed a plan for implementing the changes that will be required to transition from the currently successful screening program to the renewed program. The committee recommended that Australia move to a screening program based on testing every 5 years using an HPV test with partial genotyping with reflex liquid-based cytology (LBC) triage for HPV-vaccinated and unvaccinated women ages 25 to 69 years, and an additional exit test for women up to age 74 years. Primary HPV testing and reflex LBC will be funded by government. Symptomatic women outside the screening program will also be able to access government funded testing. The new screening program, to be rolled out in 2017, will also provide a cost-effective framework for an evaluation of the national HPV vaccination program, enabling ongoing monitoring of HPV genotypes and cervical lesions in screened women.