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.

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.

Health utilities for non-melanoma skin cancers and pre-cancerous lesions: A systematic review

BACKGROUND

Non-melanoma skin cancers (NMSCs) are common and consume many healthcare resources. A health utility is a single preference-based value for assessing health-related quality of life, which can be used in economic evaluations. There are scarce data on health utilities for NMSCs.

OBJECTIVES

Using a systematic review approach, we synthesized the current data on NMSC-related health utilities.

METHODS

A systematic review of studies of NMSC-related health utilities was conducted in Medline, Embase, and Cochrane databases. Data were extracted based on the protocol and a quality assessment was performed for each study.

RESULTS

The protocol resulted in 16 studies, involving 121 621 participants. Mean utility values across the studies ranged from 0.56 to 1 for undifferentiated NMSC, 0.84 to 1 for actinic keratosis, 0.45 to 1 for squamous cell carcinoma, and 0.67 to 1 for basal cell carcinoma. There was considerable variability in utilities by type of cancer, stage of diagnosis, time to treatment, treatment modality, and quality of life instrument or method. Utility values were predominantly based on the EuroQol 5-dimension instrument and ranged from 0.45 to 0.96, while other measurement methods produced values ranging from 0.67 to 1. Lower utility values were observed for advanced cancers and for the time period during and immediately after treatment, after which values gradually returned to pre-treatment levels.

CONCLUSIONS

Most utility values clustered around relatively high values of 0.8 to 1, suggesting small decrements in quality of life associated with most NMSCs and their precursors. Variability in utilities indicates that careful characterization is required for measures to be used in economic evaluations.

Eliminating Cervical Cancer: Progress and Challenges for High-income Countries

In 2020, the World Health Organization launched a major initiative to eliminate cervical cancer globally. The initiative is built around the three key pillars of human papillomavirus (HPV) vaccination, cervical screening and treatment, with associated intervention targets for the year 2030. The '90-70-90' targets specify that 90% of adolescent girls receive prophylactic HPV vaccination, 70% of adult women receive a minimum twice-in-a-lifetime cervical HPV test and 90% receive appropriate treatment for preinvasive or invasive disease. Modelling has shown that if these targets are met, the elimination of cervical cancer, defined as fewer than four cases per 100 000 women per annum, will be achieved within a century. Many high-income countries are well positioned to eliminate cervical cancer within the coming decades, but few have achieved '90-70-90' and many challenges must still be addressed to deliver these critical interventions effectively. This review considers the current status of cervical cancer control in relation to each of the three elimination pillars in high-income countries and discusses some of the developments that will assist countries in reaching these ambitious targets by 2030.

Human papillomavirus vaccine effectiveness within a cervical cancer screening programme: cohort study

OBJECTIVE

To assess the effectiveness of an HPV vaccination programme in reducing the risk of cervical abnormalities identified at subsequent screening.

DESIGN

Retrospective cohort study using administrative health data.

SETTING

General population of Ferrara Province, Italy.

POPULATION

Female residents born in 1986-1993 and participating in the organized cervical screening programme in 2011-2018, who were eligible for HPV vaccination in catch-up cohorts.

METHODS

Logistic regression to evaluate the potential association between abnormal cervical cytology and one, two, three or at least one dose of HPV vaccine.

MAIN OUTCOME MEASURES

Cervical abnormalities, as predicted by low-grade or high-grade cytology, by number of vaccine doses, stratified by age.

RESULTS

The sample consisted of 7785 women (mean age 27.5 years, SD 2.3). Overall, 391 (5.0%) were vaccinated with ≥1 dose and 893 (11.5%) had abnormal cytology. Women receiving at least one vaccine dose were significantly less likely to have an abnormal cytology (adjusted odds ratio 0.52; 95% confidence interval 0.34-0.79). Similar results were observed for women receiving a single dose, for both bivalent and quadrivalent vaccines, and applying buffer periods (excluding cytological outcomes within 1 month, 6 months and 1 year of the first dose).

CONCLUSIONS

In the context of an organised cervical screening programme in Italy, catch-up HPV vaccination almost halved the risk of cytological abnormalities.

TWEETABLE ABSTRACT

Among Ferrara women, vaccination against human papillomavirus halved the risk of screening cervical abnormalities.

Cancer costs and gender: a snapshot of issues, trends, and opportunities to reduce inequities using Australia as an example

As the cancer burden increases, so too does the cost, to health systems, economies, and individuals. There is increasing interest in productivity and out-of-pocket costs for individuals and their carers, but these remain poorly understood. The costs of cancer in women, often carers themselves, are less understood. This summary analysis explored data on the cancer burden in Australia (and health costs in comparable countries), including expenditure reports and literature on macroeconomic outcomes and out-of-pocket costs, to highlight the cost impacts of a cancer diagnosis in women, at a societal and an individual level. Data on productivity costs were skewed toward men, as men are over-represented in paid work compared with women. Data on societal and individual costs of cancer in women were scant, yet the predominance of women in unpaid work suggests the cost is significant. Evidence for the benefits of cancer prevention and early detection suggests that improved targeting of interventions to women would reduce costs at a societal and an individual level. More research is needed on the specific impacts of cancer on women and those they care for, to better target public health and support services to need.

Recurrent disease after treatment for cervical pre-cancer: determining whether prophylactic HPV vaccination could play a role in prevention of secondary lesions

Existing modalities can effectively treat high-grade cervical intraepithelial neoplasia (CIN) but around 7% of treated women will develop recurrence of CIN grade 2 or above within 2 years of treatment. Post-treatment surveillance is therefore required to detect residual or recurrent disease. Since the implementation of human papillomavirus (HPV) vaccination programs in high-income countries, significant reductions in high-grade CIN have been recorded in vaccinated cohorts who were predominantly HPV-naïve at vaccination. There is still debate as to the extent of potential benefit from vaccination for women previously infected with HPV, given that HPV incidence in women falls with age and previously cleared infection provides at least some protection against reinfection. Whilst vaccination-induced antibodies could prevent type-specific new infections, it is unclear whether vaccination could also prevent reactivation of latent, previously acquired infection and subsequent disease. A review of the available evidence suggests a potential reduction in risk of recurrent disease if women diagnosed and treated for CIN are offered prophylactic vaccines. New modeled analyses and, ideally, a prospectively designed randomized controlled trial in women treated and then randomized to vaccination or placebo would provide much-needed additional evidence to support the effectiveness and cost-effectiveness of offering vaccination to women after treatment for CIN.

Future Burden of Cancer Attributable to Current Modifiable Behaviours: A Pooled Study of Seven Australian Cohorts

Background: The Population Attributable Fraction (PAF) quantifies the fraction of cancer cases attributable to specific exposures. PAF estimates for the future burden of cancer preventable through modifications to current exposure distributions are lacking. Previous PAF studies have also not compared population subgroup differences. Aim: To apply a novel PAF method and i) assess the future burden of cancer in Australia preventable through modifications to current behaviors, and ii) compare the distribution of the preventable cancer burden between population subgroups. Methods: We harmonized and pooled data from seven Australian cohort studies (N=367058) and linked them to national registries to identify cancers and deaths. We estimated the strength of the associations between behaviors and cancer incidence and death using a proportional hazards model, adjusting for age, sex, study and other risk factors. Exposure prevalence was estimated from contemporary national health surveys. We then combined these estimates to calculate PAFs and their 95% confidence intervals for both individual and joint behavior modifications using a novel method accounting for competing risk of death and risk factor interdependence. We also compared PAFs between population subgroups by calculating the 95% confidence interval of the difference in PAF estimates. Results: During the first 10 years of follow-up, there were 22078 deaths and 27483 incident cancers, including 2025 lung, 3471 colorectal, 640 premenopausal and 2632 postmenopausal breast cancers. The leading preventable cause for lung cancer is current smoking (PAF = 53.7%), for colorectal and postmenopausal breast cancer body fatness or BMI ≥ 25 kg/m2 (PAF = 11.1% and 10.9% respectively), and for premenopausal breast cancer regular alcohol intake (PAF = 12.3%). Three in five lung cancers, but only one in five colorectal and breast cancers, are jointly attributable to potentially modifiable exposures, which also included physical inactivity and inadequate fruit intake for lung, excessive alcohol intake and current smoking for colorectal, regular alcohol intake and current menopausal hormone therapy for 1 year or more for postmenopausal breast and current oral contraceptive use for 5 years or more for premenopausal breast cancer. The cancer burden attributable to modifiable factors is markedly higher in certain population subgroups, including men (lung, colorectal), people with risk factor clustering (lung, colorectal, breast), and individuals with low educational attainment (lung, breast). Conclusion: We provided up-to-date estimates of the future Australian cancer burden attributable to modifiable risk factors, and identified population subgroups that experience the highest preventable burden. Application of the novel PAF method can inform timely public health action to improve health and health equity, by identifying those with the most to gain from programs that support behavior change and early detection.

Factors predicting successful DNA recovery from archival cervical smear samples

Polymerase chain reaction (PCR)-based DNA testing of archival cervical smear slides is a useful method of retrospectively establishing the presence of the human papillomavirus (HPV) in cervical cells. A cellular DNA recovery test is performed in parallel to HPV DNA testing to ensure that sufficient cells are present and purification of sample DNA has been successfully performed. Previous studies have not comprehensively assessed DNA recovery rates in slides older than 13 years. We undertook a study to determine the factors impacting DNA recovery in 436 UK slides dating from 11 to 33 years prior to testing. Overall, a low cellular DNA recovery success rate of 29% was obtained but a strong trend was observed with increasing recovery rates the older the slides (P < 0.001). Recovery rates increased from 22% in the most recent slides collected from 1988 to 1992, to 61% in the oldest slides, collected in 1970-72. It is likely that fixation compounds incorporating acetic acid, introduced in the UK through the 1980s, have compromised subsequent attempts at PCR amplification. These findings emphasize the importance of the original fixation method in the success of DNA recovery from archival smear samples.

The predicted effect of changes in cervical screening practice in the UK: results from a modelling study

In 2003, the National Health Service Cervical Screening Programme (NHSCSP) announced that its screening interval would be reduced to 3 years in women aged 25–49 and fixed at 5 years in those aged 50–64, and that women under 25 years will no longer be invited for screening. In order to assess these and possible further changes to cervical screening practice in the UK, we constructed a mathematical model of cervical HPV infection, cervical intraepithelial neoplasia and invasive cervical cancer, and of UK age-specific screening coverage rates, screening intervals and treatment efficacy. The predicted cumulative lifetime incidence of invasive cervical cancer in the UK is 1.70% in the absence of screening and 0.77% with pre-2003 screening practice. A reduction in lifetime incidence to 0.63% is predicted following the implementation of the 2003 NHSCSP recommendations, which represents a 63% reduction compared to incidence rates in the UK population if it were unscreened. The model suggests that, after the implementation of the 2003 recommendations, increasing the sensitivity of the screening test regime from its current average value of 56 to 90% would further reduce the cumulative lifetime incidence of invasive cervical cancer to 0.46%. Alternatively, extending screening to women aged 65–79 years would further reduce the lifetime incidence to 0.56%. Screening women aged 20–25 years would have minimal impact, with the cumulative lifetime incidence decreasing from 0.63 to 0.61%. In conclusion, the study supports the 2003 recommendations for changes to cervical screening intervals.

A real time optoelectronic device as an adjunct to the Pap smear for cervical screening: A multicenter evaluation

We report on the results from a multicenter trial for a real time optoelectronic device as an adjunct to the Pap smear for cervical screening. TruScreen (Polartechnics Limited, Sydney, Australia) is an automated device which measures the response to optical and electrical stimulation of the cervix and returns a screening result in real time. Analysis was performed on a group of 651 subjects recruited at 10 centers. Cytology and histology analyses were performed by centralized laboratories, with the cytology classification performed according to the Bethesda 2001 system. The sensitivities for histologically confirmed CIN 2/3 lesions by TruScreen, Pap, and TruScreen/Pap combined were 70% (95% CI: 67-74), 69% (CI: 65-72), and 93% (CI: 91-95), respectively. For histologically reported CIN 1, the sensitivities of the TruScreen, Pap, and combined test were 67% (CI: 63-70), 45% (CI: 41-49), and 87% (CI: 84-89). The improvement in sensitivity for the combined test compared to the Pap smear alone was significant (P = 0.002). Because TruScreen and cytology detect partly different but overlapping groups of CIN cases, the adjunctive combination provides very high CIN detection rates.

A real time optoelectronic device as an adjunct to the Pap smear for cervical screening: A multicenter evaluation

We report on the results from a multicenter trial for a real time optoelectronic device as an adjunct to the Pap smear for cervical screening. TruScreen (Polartechnics Limited, Sydney, Australia) is an automated device which measures the response to optical and electrical stimulation of the cervix and returns a screening result in real time. Analysis was performed on a group of 651 subjects recruited at 10 centers. Cytology and histology analyses were performed by centralized laboratories, with the cytology classification performed according to the Bethesda 2001 system. The sensitivities for histologically confirmed CIN 2/3 lesions by TruScreen, Pap, and TruScreen/Pap combined were 70% (95% CI: 67–74), 69% (CI: 65–72), and 93% (CI: 91–95), respectively. For histologically reported CIN 1, the sensitivities of the TruScreen, Pap, and combined test were 67% (CI: 63–70), 45% (CI: 41–49), and 87% (CI: 84–89). The improvement in sensitivity for the combined test compared to the Pap smear alone was significant (P = 0.002). Because TruScreen and cytology detect partly different but overlapping groups of CIN cases, the adjunctive combination provides very high CIN detection rates.

The Polarprobe--emerging technology for cervical cancer screening

The Polarprobe is a portable non invasive electronic device designed for the detection of cervical precancer and cancer. It measures both electrical and optical properties of cervical tissue to allow a real time comparison with a databank of previously determined cervical tissue types. The need for additional tests to augment or even replace the Papanicolaou smear has partly prompted its development. Indeed it has been shown to be associated with less pain and anxiety than the smear and has the capability of encouraging women to attend for screening. Some of the preliminary clinical trials on the Polarprobe are reported as well as the ongoing developments and modifications to the device.