Working together with people with intellectual disability to make a difference: a protocol for a mixed-method co-production study to address inequities in cervical screening participation.

Introduction: Cervical cancer is one of the most preventable cancers yet remains a disease of inequity for people with intellectual disability, in part due to low screening rates. The ScreenEQUAL project will use an integrated knowledge translation (iKT) model to co-produce and evaluate accessible cervical screening resources with and for this group. Methods: Stage 1 will qualitatively explore facilitators and barriers to screening participation for people with intellectual disability, families and support people, healthcare providers and disability sector stakeholders (n ≈ 20 in each group). An accessible multimodal screening resource, accompanying supporting materials for families and support people, and trauma-informed healthcare provider training materials will then be co-produced through a series of workshops. Stage 2 will recruit people with intellectual disability aged 25 to 74 who are due or overdue for screening into a single-arm trial (n = 48). Trained support people will provide them with the co-produced resource in accessible workshops (intervention) and support them in completing pre-post questions to assess informed decision-making. A subset will participate in qualitative post-intervention interviews including optional body-mapping (n ≈ 20). Screening uptake in the 9-months following the intervention will be measured through data linkage. Family members and support people (n = 48) and healthcare providers (n = 433) will be recruited into single-arm sub-studies. Over a 4-month period they will, respectively, receive the accompanying supporting materials, and the trauma-informed training materials. Both groups will complete pre-post online surveys. A subset of each group (n ≈ 20) will be invited to participate in post-intervention semi-structured interviews. Outcomes and analysis: Our primary outcome is a change in informed decision-making by people with intellectual disability across the domains of knowledge, attitudes, and screening intention. Secondary outcomes include: (i) uptake of screening in the 9-months following the intervention workshops, (ii) changes in health literacy, attitudes and self-efficacy of family members and support people, and (iii) changes in knowledge, attitudes, self-efficacy and preparedness of screening providers. Each participant group will evaluate acceptability, feasibility and usability of the resources. Discussion: If found to be effective and acceptable, the co-produced cervical screening resources and training materials will be made freely available through the ScreenEQUAL website to support national, and potentially international, scale-up.

Participation in the national cervical screening programme among women from New South Wales, Australia, by place of birth and time since immigration: A data linkage analysis using the 45 and up study.

OBJECTIVE: Equitable elimination of cervical cancer in Australia within the next decade will require high National Cervical Screening Program (NCSP) participation by all subgroups of women. The aim of this study was to examine the participation of immigrants compared to Australian-born women. METHODS: Participation in the NCSP (≥1cytology test) over a 3-year (2010-2012) and 5-year (2008-2012) period, by place of birth and time since immigration was examined using individually linked data of 67,350 New South Wales (NSW) women aged ≥45 enrolled in the 45 and Up Study. RESULTS: Three-year cervical screening participation was 77.0% overall. Compared to Australian-born women (77.8%), 3-year participation was lower for women born in New Zealand (adjusted odds ratio 0.77, 95% confidence interval 0.69-0.87), Oceania (0.67, 0.51-0.89), Middle East/North Africa (0.76, 0.60-0.97), South-East Asia (0.72, 0.60-0.87), Chinese Asia (0.82, 0.69-0.97), Japan/South Korea (0.68, 0.50-0.94), and Southern/Central Asia (0.54, 0.43-0.67), but higher for women from Malta (2.85, 1.77-4.58) and South America (1.33, 1.01-1.75). Non-English-speaking-at-home women were less likely to be screened than English-speaking-at-home women (0.85, 0.78-0.93). Participation increased with years lived in Australia but remained lower in immigrant groups compared to Australian-born women, even after ≥20 years living in Australia. Similar results were observed for 5-year participation. CONCLUSIONS: Women born in New Zealand, Oceania, and parts of Asia and the Middle East had lower NCSP participation, which persisted for ≥20 years post-immigration. The NCSP transition to primary HPV screening, and the introduction of the universal self-collection option in 2022, will offer new opportunities for increasing screening participation for these groups.

Understanding women's choices for management of cervical intraepithelial neoplasia 2 (CIN2): Qualitative analysis of a randomised experimental study.

BACKGROUND: Active surveillance for cervical intraepithelial neoplasia 2 (CIN2) would allow time for most cases to regress naturally and in turn avoid potentially unnecessary and harmful treatment. AIM: To determine reasons for choosing active surveillance over surgery among women given a hypothetical diagnosis of CIN2. MATERIALS AND METHODS: Women residing in Australia aged 25-40 years with no prior diagnosis of cervical cancer, cervical abnormality CIN2 or above, and/or previous hysterectomy, were randomised to one of four identical hypothetical scenarios of testing human papillomavirus (HPV)-positive: high-grade cytology and a diagnosis of CIN2 that used alternate terminology to describe resolution of abnormal cells and/or inclusion of an overtreatment statement. Participants selected active surveillance or surgery after viewing the scenario and free-text reason/s for their choice were thematically analysed. RESULTS: Of the 1638 women randomised, 79% (n = 1293) opted for active surveillance. The most common reasons for choosing active surveillance included concerns about surgery and associated risks, preferring to 'wait and see', trusting the doctor's recommendations and having an emotional response toward surgery. For women who chose surgery, being risk-averse, addressing the issue straight away and perceiving surgery to be the better option for them were the most common themes identified. CONCLUSION: When presented with balanced information on the benefits and harms of different management options for CIN2 and given a choice, most women in this hypothetical situation chose active surveillance over surgery. Addressing women's concerns about active surveillance may open up the possibility that if deemed safe, it could be an acceptable alternative for women.

Best Practice Contraception Care for Women with Obesity: A Review of Current Evidence.

The prevalence of obesity among females of reproductive age is increasing globally. Access to the complete range of appropriate contraceptive options is essential for upholding the reproductive rights of this population group. People with obesity can experience stigma and discrimination when seeking healthcare, and despite limited evidence for provider bias in the context of contraception, awareness for its potential at an individual provider and health systems level is essential. While use of some hormonal contraceptives may be restricted due to increased health risks in people with obesity, some methods provide noncontraceptive benefits including a reduced risk of endometrial cancer and a reduction in heavy menstrual bleeding which are more prevalent among individuals with obesity. In addition to examining systems-based approaches which facilitate the provision of inclusive contraceptive care, including long-acting reversible contraceptives which require procedural considerations, this article reviews current evidence on method-specific advantages and disadvantages for people with obesity to guide practice and policy.

The impact of HPV vaccination beyond cancer prevention: effect on pregnancy outcomes.

While the benefits of human papillomavirus (HPV) vaccination relating to cervical cancer prevention have been widely documented, recent published evidence is suggestive of an impact on adverse pregnancy outcomes (APOs) in vaccinated mothers and their infants, including a reduction in rates of preterm births and small for gestational age infants. In this review, we examine this evidence and the possible mechanisms by which HPV vaccination may prevent these APOs. Large-scale studies linking HPV vaccination status with birth registries are needed to confirm these results. Potential confounding factors to consider in future analyses include other risk factors for APOs, and historical changes in both the management of cervical precancerous lesions and prevention of APOs. If confirmed, these additional benefits of HPV vaccination in reducing APO rates will be of global significance, due to the substantial health, social and economic costs associated with APOs, strengthening the case for worldwide HPV immunization.

Human papillomavirus prevalence and risk factors among Australian women 9-12 years after vaccine program introduction.

BACKGROUND: In Australia, high and widespread uptake of the quadrivalent human papillomavirus (HPV) vaccine has led to substantial population-level reductions in the prevalence of quadrivalent vaccine targeted HPV genotypes 6/11/16/18 in women aged ≤ 35 years. We assessed risk factors for HPV detection among 18-35 year old women, 9-12 years after vaccine program introduction. METHODS: Women attending health services between 2015 and 2018 provided a self-collected vaginal specimen for HPV genotyping (Roche Linear Array) and completed a questionnaire. HPV vaccination status was validated against the National Register. Adjusted odds ratios (aORs) and 95% confidence intervals (CI) were calculated for factors associated with HPV detection. RESULTS: Among 1564 women (median age 24 years; IQR 21-27 years), Register-confirmed ≥ 1-dose vaccine coverage was highest at 69.3% and 68.1% among women aged 18-21 and 22-24 years respectively, decreasing to 42.9% among those aged 30-35 years. Overall prevalence of quadrivalent vaccine-targeted HPV types was very low (2.0%; 95% CI: 1.4-2.8%) and influenced only by vaccination status (5.5% among unvaccinated compared with 0.7% among vaccinated women; aOR = 0.13 (95% CI: 0.05-0.30)). Prevalence of remaining HPV types, at 40.4% (95% CI: 38.0-42.9%), was influenced by established risk factors for HPV infection; younger age-group (p-trend < 0.001), more recent (p < 0.001) and lifetime sexual partners (p-trend < 0.001), but not vaccination status. Prevalence of HPV31/33/45, which shared risk factors with that of non-vaccine targeted HPV types, was also lower among vaccinated (4%) compared with unvaccinated (7%) women (aOR = 0.51; 95% CI: 0.29-0.89), indicative of cross-protection. CONCLUSION: Vaccination has changed the epidemiology of HPV infection in Australian women, having markedly reduced the prevalence of vaccine-targeted types, including amongst women with known risk factors for infection. Vaccinated women appear to be benefiting from modest cross-protection against types 31/33/45 afforded by the quadrivalent HPV vaccine. These results reinforce the importance of HPV vaccination.

Active surveillance as a management option for cervical intraepithelial neoplasia 2: An online experimental study.

OBJECTIVE: To investigate framing of active surveillance as a management option for cervical intraepithelial neoplasia (CIN)2 in women of childbearing age. METHODS: We conducted a between-subjects factorial (2 × 2) randomised experiment. Women aged 25-40 living in Australia were presented with the same hypothetical pathway of testing human papillomavirus (HPV)-positive, high-grade cytology and a diagnosis of CIN2, through an online survey. They were randomised to one of four groups to evaluate the effects of (i) framing (method of explaining resolution of abnormal cells) and (ii) inclusion of an overtreatment statement (included versus not). Primary outcome was management choice following the scenario: active surveillance or surgery. RESULTS: 1638 women were randomised. Overall, preference for active surveillance was high (78.9%; n = 1293/1638). There was no effect of framing or providing overtreatment information, or their interaction, on management choice. After adjusting for intervention received, age, education, and other model covariates, participants were more likely to choose active surveillance over surgery if they had not already had children, had plans for children in the future, had no family history of cancer, had no history of endometriosis, had adequate health literacy, and more trust in their GP. Participants were less likely to choose active surveillance over surgery if they were more predisposed to seek health care for minor problems. CONCLUSIONS: Although we found no framing effect across the four conditions, we found a high level of preference for active surveillance with associations of increased preference that accord with the desire to minimise potential risks of CIN2 treatment on obstetric outcomes. These are valuable data for future clinical trials of active surveillance for management of CIN2 in younger women of childbearing age. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12618002043213, 20/12/2018, prior to participant enrolment).

Could HPV Testing on Self-collected Samples Be Routinely Used in an Organized Cervical Screening Program? A Modeled Analysis.

BACKGROUND: Cervical screening on self-collected samples has mainly been considered for targeted use in underscreened women. Updated evidence supports equivalent sensitivity of PCR-based human papillomavirus (HPV) testing on self-collected and clinician-collected samples. METHODS: Using a well-established model, we compared the lifetime impact on cancer diagnoses and deaths resulting from cervical screening using self-collected samples only, with and without the existing restriction in Australia to women aged 30+ years and ≥2 years overdue, compared with the mainstream program of 5-yearly HPV screening on clinician-collected samples starting at 25 years of age. We conservatively assumed sensitivity of HPV testing on self-collected relative to clinician-collected samples was 0.98. Outcomes were estimated either in the context of HPV vaccination ("routinely vaccinated cohorts;" uptake as in Australia) or in the absence of HPV vaccination ("unvaccinated cohorts"). RESULTS: In unvaccinated cohorts, the health benefits of increased participation from self-collection outweighed the worst case (2%) loss of relative test sensitivity even if only 15% of women, who would not otherwise attend, used it ("additional uptake"). In routinely vaccinated cohorts, population-wide self-collection could be marginally (0.2%-1.0%) less effective at 15% additional uptake but 6.2% to 12.4% more effective at 50% additional uptake. Most (56.6%-65.0%) of the loss in effectiveness in the restricted self-collection pathway in Australia results from the requirement to be 2 or more years overdue. CONCLUSIONS: Even under pessimistic assumptions, any potential loss in test sensitivity from self-collection is likely outweighed by improved program effectiveness resulting from feasible levels of increased uptake. IMPACT: Consideration could be given to offering self-collection more widely, potentially as an equal choice for women.See related commentary by Lim, p. 245.

Unwanted Sex Due to Intoxication among Australians Aged 16-69 Years.

Intoxication can be a factor in unwanted sex, but research on the extent of the issue in both women and men is limited. We assessed the prevalence, correlates, and 10-year time-trends of unwanted sex due to intoxication among a representative sample of 4,279 women and 3,875 men aged 16-69 years in Australia and considered how these vary by gender. In 2012-13, 16% of women and 10% of men reported ever having had a sexual experience when they "did not want to because they were too drunk or high at the time." For both women and men, this was associated with younger age, bisexual activity, and reports of lifetime injection drug use, sexually transmitted infections, and forced sex. Among women only, it was associated with drinking above guideline levels and ever having terminated a pregnancy. Among men only, it was associated with current tobacco smoking, elevated psychosocial distress, and poor general health. Compared with 2001-02 data, fewer men reported unwanted intoxicated sex, while there were no changes for women as a whole. Interpreting these findings through an intersectional assemblage framework supports stronger understanding of the multiple factors influencing sexuality and substance use with implications for promoting equity, safety, and sexual health.

The impact of cancer-related fertility concerns on current and future couple relationships: People with cancer and partner perspectives.

OBJECTIVE: The purpose of this study was to examine how cancer-related fertility concerns impact on couple relationships from the perspectives of people with cancer (PWC) and partners of people with cancer. METHODS: A qualitative research design was used, drawing data from open-ended responses to a survey and in-depth individual interviews. Eight hundred and seventy-eight PWC (693 women, 185 men) and 144 partners (82 women, 62 men), across a range of tumour types and age groups, completed a survey, and 78 PWC (61 women and 17 men) and 26 partners (13 women and 13 men), participated in semi-structured interviews. RESULTS: Thematic analysis identified that many PWC and partners experience a 'double burden', manifested by cancer-related fertility concerns creating relational stress, changes to couple sexual intimacy and feelings of inadequacy when forming new relationships. However, many participants adopted strategies to facilitate coping with infertility or fertility concerns. This included acceptance of infertility and privileging of survival, focusing on relationship growth, optimism and nurturing in other ways. CONCLUSION: Cancer-related fertility concerns can have a significant impact on couple relationships. Psychological support from clinicians may facilitate couple coping, as well as help to address concerns about future relationships for un-partnered people with cancer.

National Cervical Screening Program renewal in Australia: survey of clinician views and attitudes.

From 1 December 2017, the National Cervical Screening Program was renewed in Australia, with updated national cervical screening guidelines released. This study was performed to determine clinicians' familiarity with the updated guidelines and explore their views and attitudes towards the renewed program. Clinicians providing cervical screening in New South Wales, Australia, were invited to complete an online survey in 2018. Of the 241 clinicians who responded, 91.5% supported the change to 5-yearly human papillomavirus screening from the age of 25 years. However, nearly 13% indicated they did not know where to access the renewed guidelines and 37% had never or rarely accessed them. Open-ended responses highlighted clinicians' concerns about missed cancers and missed opportunities for health checks. Those raising these concerns accessed the guidelines less frequently. The findings highlight important areas for additional education and support for clinicians in translating guidelines into practice to ensure successful delivery of the renewed program.

Has Human Papillomavirus (HPV) Vaccination Prevented Adverse Pregnancy Outcomes? Population-Level Analysis After 8 Years of a National HPV Vaccination Program in Australia.

BACKGROUND: Human papillomavirus (HPV) infection, and its sequelae of precancerous cervical lesions and their subsequent treatment, have been linked with an increased risk of adverse pregnancy outcomes. Publicly funded HPV vaccination of female adolescents began in Australia in 2007 with initial catch-up to age 26 years. METHODS: Using data from the National Perinatal Data Collection we compared rates of preterm births and small-for-gestational-age infants born in Australia 2000-2015. We used generalized linear models, assuming a Poisson distribution and log link function, with single-year categories of infant birth year, maternal age, and age-specific HPV vaccination coverage as independent variables. RESULTS: In maternal cohorts with 60%-80% HPV vaccination coverage as achieved in Australia, there was a relative rate reduction of 3.2% (95% confidence interval, 1.1%-5.3%) in preterm births and 9.8% (8.2% to 11.4%) in small-for-gestational-age infants, after adjustment for infant's birth year and maternal age. CONCLUSION: This analysis provides provisional population-level evidence of a reduction in adverse pregnancy outcomes in cohorts of women offered HPV vaccination. Confounding by smoking or other variables and/or ecological analysis limitations, however, cannot be excluded. These findings indicate potential broader benefits of HPV vaccination than have been documented to date.

Pathways to a cancer-free future: A protocol for modelled evaluations to maximize the future impact of interventions on cervical cancer in Australia.

OBJECTIVE: Australia's HPV vaccination and HPV-based cervical screening programs are changing the landscape in cervical cancer prevention. We aim to identify areas which can make the biggest further impact on cervical cancer burden. This protocol describes the first stage of a program of work called Pathways-Cervix that aims to generate evidence from modelled evaluations of interventions across the cervical cancer spectrum. METHODS: Based on evidence from literature reviews and guidance from a multi-disciplinary Scientific Advisory Committee (SAC), the most relevant evaluations for prevention, diagnosis and treatment were identified. RESULTS: Priority evaluations agreed by the SAC included: increasing/decreasing and retaining vaccination uptake at the current level; vaccinating older women; increasing screening participation; methods for triaging HPV-positive women; improving the diagnosis of cervical intraepithelial neoplasia (CIN) and cancer; treating cervical abnormalities and cancer; and vaccinating women treated for CIN2/3 to prevent recurrence. Evaluations will be performed using a simulation model, Policy1-Cervix previously used to perform policy evaluations in Australia. Exploratory modelling of interventions using idealised scenarios will initially be conducted in single birth cohorts. If these have a significant impact on findings then evaluations with more realistic assumptions will be conducted. Promising strategies will be investigated further by multi-cohort simulations predicting health outcomes, resource use and cost outcomes. CONCLUSIONS: Pathways-Cervix will assess the relative benefits of strategies and treatment options in a systematic and health economic framework, producing a list of 'best buys' for future decision-making in cervical cancer control.

Very Low Prevalence of Vaccine Human Papillomavirus Types Among 18- to 35-Year Old Australian Women 9 Years Following Implementation of Vaccination.

Introduction: A quadrivalent human papillomavirus vaccination program targeting females aged 12-13 years commenced in Australia in 2007, with catch-up vaccination of 14-26 year olds through 2009. We evaluated the program's impact on HPV prevalence among women aged 18-35 in 2015. Methods: HPV prevalence among women aged 18-24 and 25-35 was compared with prevalence in these age groups in 2005-2007. For women aged 18-24, we also compared prevalence with that in a postvaccine study conducted in 2010-2012. Results: For the 2015 sample, Vaccination Register-confirmed 3-dose coverage was 53.3% (65.0% and 40.3% aged 18-24 and 25-35, respectively). Prevalence of vaccine HPV types decreased from 22.7% (2005-2007) and 7.3% (2010-2012), to 1.5% (2015) (P trend < .001) among women aged 18-24, and from 11.8% (2005-2007) to 1.1% (2015) (P = .001) among those aged 25-35. Conclusions: This study, reporting the longest surveillance follow-up to date, shows prevalence of vaccine-targeted HPV types has continued to decline among young women. A substantial fall also occurred in women aged 25-35, despite lower coverage. Strong herd protection and effectiveness of less than 3 vaccine doses likely contributed to these reductions.

How will transitioning from cytology to HPV testing change the balance between the benefits and harms of cervical cancer screening? Estimates of the impact on cervical cancer, treatment rates and adverse obstetric outcomes in Australia, a high vaccination coverage country.

Primary HPV screening enables earlier diagnosis of cervical lesions compared to cytology, however, its effect on the risk of treatment and adverse obstetric outcomes has not been extensively investigated. We estimated the cumulative lifetime risk (CLR) of cervical cancer and excisional treatment, and change in adverse obstetric outcomes in HPV unvaccinated women and cohorts offered vaccination (>70% coverage in 12-13 years) for the Australian cervical screening program. Two-yearly cytology screening (ages 18-69 years) was compared to 5-yearly primary HPV screening with partial genotyping for HPV16/18 (ages 25-74 years). A dynamic model of HPV transmission, vaccination, cervical screening and treatment for precancerous lesions was coupled with an individual-based simulation of obstetric complications. For cytology screening, the CLR of cervical cancer diagnosis, death and treatment was estimated to be 0.649%, 0.198% and 13.4% without vaccination and 0.182%, 0.056% and 6.8%, in vaccinated women, respectively. For HPV screening, relative reductions of 33% and 22% in cancer risk for unvaccinated and vaccinated women are predicted, respectively, compared to cytology. Without the implementation of vaccination, a 4% increase in treatment risk for HPV versus cytology screening would have been expected, implying a possible increase in pre-term delivery (PTD) and low birth weight (LBW) events of 19 to 35 and 14 to 37, respectively, per 100,000 unvaccinated women. However, in vaccinated women, treatment risk will decrease by 13%, potentially leading to 4 to 41 fewer PTD events and from 2 more to 52 fewer LBW events per 100,000 vaccinated women. In unvaccinated women in cohorts offered vaccination as 12-13 year olds, no change to lifetime treatment risk is expected with HPV screening. In unvaccinated women in cohorts offered vaccination as 12-13 year olds, no change to lifetime treatment risk is expected with HPV screening. HPV screening starting at age 25 in populations with high vaccination coverage, is therefore expected to both improve the benefits (further decrease risk of cervical cancer) and reduce the harms (reduce treatments and possible obstetric complications) associated with cervical cancer screening.

Perimenopausal contraception: A practice-based approach.

BACKGROUND: Women who are perimenopausal are at risk of unintended pregnancy despite relatively low fertility at this stage. Contraceptive choice can be limited by increased comorbidities, but the UK Medical Eligibility Criteria (UKMEC) system provides a framework for safe prescribing. OBJECTIVE: This article provides evidence-based guidance on contraceptive options, and information to support decision-making about stopping contraception at menopause. DISCUSSION: Contraceptive choice is determined by several factors, including medical eligibility, side effects and risks, non-contraceptive benefits, cost and personal preference. Long-acting reversible contraceptives (LARCs) are an effective, acceptable and safe choice for many women. For women aged ≥50 years who are using a non-hormonal method, contraception is recommended until after 12 months of amenorrhoea, or 24 months if they are aged 50 years; serial follicle-stimulating hormone (FSH) levels can guide method cessation given amenorrhoea is not a reliable indicator of menopause in this context.

Teenage mothers.

BACKGROUND: Australia's teenage birth rate has fallen to historic lows, but teenage motherhood still occurs and can be challenging for mother and baby. OBJECTIVE: The aim of this article is to review current evidence on the epidemiology and clinical care of teenage pregnancy and parenting, and provide recommendations around management of these young people in Australia. DISCUSSION: Teenage mothers may have experienced family, sexual, and partner violence, family disruption, and socioeconomic disadvantage. Outcomes on a range of peripartum measures are worse for teenage mothers and their babies. Longer term risks for the mother include depression and rapid repeat pregnancy; for the child, intergenerational teenage parenthood; and for both, socioeconomic disadvantage. Teenage motherhood occurs more often within communities where poverty, Aboriginal and Torres Strait Islander status and rural/remote location intersect. General practitioners play a critical role in identification of at-risk teens, preventing unintended teenage pregnancy, clinical care of pregnant teens, and promoting the health and wellbeing of teenage mothers and their children.

Assessment of herd immunity and cross-protection after a human papillomavirus vaccination programme in Australia: a repeat cross-sectional study.

BACKGROUND: After the introduction of a quadrivalent human papillomavirus (HPV) vaccination programme in Australia in April, 2007, we measured the prevalence of vaccine-targeted and closely related HPV types with the aim of assessing direct protection, cross-protection, and herd immunity. METHODS: In this repeat cross-sectional study, we recruited women aged 18-24 years who attended Pap screening between October, 2005, and July, 2007, in three major metropolitan areas of Australia to form our prevaccine-implementation sample. For our postvaccine-implementation sample, we recruited women aged 18-24 years who attended Pap screening in the same three metropolitan areas from August, 2010, to November, 2012. We compared the crude prevalence of HPV genotypes in cervical specimens between the prevaccine and the postvaccine implementation groups, with vaccination status validated against the National HPV Vaccination Program Register. We estimated adjusted prevalence ratios using log linear regression. We estimated vaccine effectiveness both for vaccine-targeted HPV types (16, 18, 6, and 11) and non-vaccine but related HPV types (31, 33, and 45). FINDINGS: 202 women were recruited into the prevaccine-implementation group, and 1058 were recruited into the postvaccine-implementation group. Crude prevalence of vaccine-targeted HPV genotypes was significantly lower in the postvaccine-implementation sample than in the prevaccine-implementation sample (58 [29%] of 202 vs 69 [7%] of 1058; p<0·0001). Compared with the prevaccine-implementation sample, adjusted prevalence ratios for vaccine-targeted HPV genotypes were 0·07 (95% CI 0·04-0·14; p<0·0001) in fully vaccinated women and 0·65 (0·43-0·96; p=0·03) in unvaccinated women, which suggests herd immunity. No significant declines were noted for non-vaccine-targeted HPV genotypes. However, within the postvaccine-implementation sample, adjusted vaccine effectiveness against vaccine-targeted HPV types for fully vaccinated women compared with unvaccinated women was 86% (95% CI 71-93), and was 58% (26-76) against non-vaccine-targeted but related genotypes (HPV 31, 33, and 45). INTERPRETATION: 6 years after the initiation of the Australian HPV vaccination programme, we have detected a substantial fall in vaccine-targeted HPV genotypes in vaccinated women; a lower prevalence of vaccine-targeted types in unvaccinated women, suggesting herd immunity; and a possible indication of cross-protection against HPV types related to the vaccine-targeted types in vaccinated women. FUNDING: Australian National Health and Medical Research Council and Cancer Council Victoria.