HPV-vaccination impact in Denmark: is the vaccine working?

What are parents' preferences for Human Papillomavirus vaccination promotion messages and communication? Application of a discrete choice experiment to a French Caribbean setting

INTRODUCTION

Human Papillomavirus (HPV) vaccine uptake in the French Caribbean has remained below 25% since introduction in 2007, which is well behind national and international targets. Using a discrete choice experiment (DCE), we explored parental preferences around HPV vaccination and optimized communication content in a sample of parents of middle-school pupils in Guadeloupe.

METHODS

We conducted a cross-sectional survey in public and private middle age schools in Guadeloupe in June 2023 using an online questionnaire. Across a series of nine hypothetical scenarios, participants were asked to decide to vaccinate or not and how certain they were about this choice. Scenarios differed by five attributes (diseases characteristics, vaccine safety, health professionals or institutions promoting vaccination, social conformity and optimal vaccination age). We used random effect logit and linear regression models to estimate the effects of attribute levels on vaccine acceptance and vaccine eagerness.

RESULTS

A total of 389 parents out of the 23,184 pupils' parents completed the DCE survey. The attributes with a significant effect size on theoretical vaccine acceptance were "social conformity" and "optimal vaccination age". Overall, the odds of scenarios stating high vaccine coverage in adolescents were at least 1.8 (95% CI: 1.2-2.6) times more likely to yield theoretical vaccine acceptance compared to a low vaccine uptake reference. The odds of providing scientific explanation along with age yielded theoretical vaccination acceptance respectively up to 3.2 times higher (95% CI: 1.7 to 6.1) in parents reporting an un vaccinated child and not intention to vaccinate. For vaccine eagerness, we observe significant positive effects of communication content overall when stating high vaccination uptake in adolescents or scientific evidence along with age or mentioning cancer prevention. Parents always refusing vaccination remained unsensitive to communication contents.

DISCUSSION AND CONCLUSION

These original DCE results highlighted the need for tailoring specific HPV vaccination promotion communication in a French Caribbean setting. Contextual features such as sexuality concerns as regard to age and peers' adhesion to vaccination have to be thoroughly considered. The nationwide HPV vaccination campaign in middle schools should adapt communication in order to raise HPV vaccine uptake in the French Caribbean.

Cervical cancer incidence in Denmark: Disentangling determinants of time trend

Cervical cancer is a preventable disease. Nevertheless, stagnation has been seen in incidence rates also in countries with well-functioning healthcare. On this basis, we investigated associations between control interventions and changes in cervical cancer incidence in Denmark from 2009 to 2022. Data on human papillomavirus (HPV)-vaccination were retrieved from Staten's Serum Institute; on screening recommendations from Danish Health Authority, on screening performance from Danish Quality Database for Cervical Screening; and on cervical cancer incidence from Nordcan and Danish Cancer Register. We reported coverage with HPV vaccination (1+ dose); coverage with cervical cell samples; number of women with primary HPV tests; proportion of non-normal cell samples without timely follow-up; number of conizations; and cervical cancer incidence rates. In 2022, all women aged ≤29 had been offered childhood HPV vaccination with coverage of 80%-90%. By 2020-2022, the cervical cancer incidence rate in women aged 20-29 was 3 per 100,000; at level of disease elimination. In 2017, women aged 70+ were offered a one-time HPV screening, and by 2020-2022, the old-age peak in cervical cancer incidence had largely disappeared. From 2009 to 2022, proportion of non-normal cell samples without timely follow-up decreased from 20% to 10%, and conventional cytology was largely replaced by SurePath liquid-based cytology; these factors could explain the steady decrease in cervical cancer incidence rate. Implementation of primary HPV screening in women aged 30-59 in 2021 was reflected in a, probably temporary, increase in the 2022 cervical cancer incidence rate. In conclusion, combined interventions with childhood HPV vaccination; one-time HPV screening of elderly women; and better management of screening broke previous stagnation in cervical cancer incidence rate.

Screening outcome of HPV-vaccinated women: Data from the Danish Trial23 cohort study

BACKGROUND

Danish women-who were HPV-vaccinated as girls-are now reaching an age where they are invited to cervical cancer screening. Because of their expected lower cervical cancer risk, we must reassess our screening strategies. We analyzed Danish HPV-vaccinated women's outcomes after the first screening test at age 23.

METHODS AND FINDINGS

Our study was embedded in Danish routine cytology-based screening. We conducted an observational study and included women born in 1994, offered the 4-valent HPV vaccine at age 14, and subsequently invited to screening at age 23. Cervical cytology was used for diagnostics and clinical management. Residual material was HPV tested with Cobas® 4800/6800. The most severe histology diagnosis within 795 days of screening was found through linkage with the Danish National Pathology Register. We calculated the number of women undergoing follow-up (repeated testing and/or colposcopy) per detected cervical intraepithelial neoplasia (CIN2+). A total of 6021 women were screened; 92% were HPV-vaccinated; 12% had abnormal cytology; 35% were high-risk HPV-positive, including 0.9% HPV16/18 positive, and 20% had follow-up. In women that were cytology-abnormal and HPV-positive (Cyt+/HPV+), 610 (98.5%) had been followed up, and 138 CIN2+ cases were diagnosed, resulting in 4.4 (95% CI 3.9-5.2) women undergoing follow-up per detected CIN2+. In contrast to recommendations, 182 (12.2%) cytology-normal and HPV-positive (Cyt-/HPV+) women were followed up within 795 days, and 8 CIN2+ cases were found, resulting in 22.8 (95% CI 13.3-59.3) women undergoing follow-up per detected CIN2+.

CONCLUSION

Overall, HPV prevalence was high in HPV-vaccinated women, but HPV16/18 had largely disappeared. In the large group of cytology-normal and HPV-positive women, 23 had been followed up per detected CIN2+ case. Our data indicated that primary HPV screening of young HPV-vaccinated women would require very effective triage methods to avoid an excessive follow-up burden.

TRIAL REGISTRATION

Trial registration number: NCT0304955.

School-Level Variation in Coverage of Co-Administered dTpa and HPV Dose 1 in Three Australian States

BACKGROUND

Australian adolescents are routinely offered HPV and dTpa (diphtheria, tetanus, pertussis) vaccines simultaneously in the secondary school vaccination program. We identified schools where HPV initiation was lower than dTpa coverage and associated school-level factors across three states.

METHODS

HPV vaccination initiation rates and dTpa vaccination coverage in 2016 were calculated using vaccine databases and school enrolment data. A multivariate analysis assessed sociodemographic and school-level factors associated with HPV initiation being >5% absolute lower than dTpa coverage.

RESULTS

Of 1280 schools included, the median school-level HPV initiation rate was 85% (interquartile range (IQR):75-90%) and the median dTpa coverage was 86% (IQR:75-92%). Nearly a quarter (24%) of all schools had HPV vaccination initiation >5% lower than dTpa coverage and 11 % had >10% difference. School-level factors independently associated with >5% difference were remote schools (aOR:3.5, 95% CI = 1.7-7.2) and schools in major cities (aOR:1.8, 95% CI = 1.0-3.0), small schools (aOR:3.3, 95% CI = 2.3-5.7), higher socioeconomic advantage (aOR:1.7, 95% CI = 1.1-2.6), and lower proportions of Language-background-other-than-English (aOR:1.9, 95% CI = 1.2-3.0).

CONCLUSION

The results identified a quarter of schools had lower HPV than dTpa initiation coverage, which may indicate HPV vaccine hesitancy, and the difference was more likely in socioeconomically advantaged schools. As hesitancy is context specific, it is important to understand the potential drivers of hesitancy and future research needs to understand the reasons driving differential uptake.

Management of low-grade cervical cytology in young women. Cohort study from Denmark

OBJECTIVE

Cytology findings of atypical squamous cells of unknown significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) are common among women under 30, but evidence on best management strategy is insufficient. We therefore investigated how different management strategies used in Denmark influenced biopsy rates and detection of cervical intraepithelial neoplasia (CIN).

METHODS

Register-based cohort study including Danish women aged less than 30 years and born 1980-95, with ASCUS/LSIL as their first abnormal cervical cytology in 2008-16. Rates and relative risks (RR) of biopsy and detection of CIN3+, CIN2 and < CIN2 during two years follow-up were compared between women referred directly to colposcopy after ASCUS/LSIL or undergoing additional testing, including mRNA or DNA test for high risk HPV or repeat cytology.

RESULTS

19,946 women with ASCUS and 19,825 with LSIL were included in the study of whom 92% had adequate information about follow-up. Among women referred directly to biopsy, CIN3+ was detected among 21%, CIN2 in 17%, while 62% had < CIN2. Repeating cytology after 6 months reduced the biopsy rate to 44% of which 53% had < CIN2. Biopsy rates with HPV test were 67% for DNA test, 77% with 14-type mRNA test and 58% with 5-type mRNA test. The detection of CIN3+ was somewhat higher, between 13% and 14% for the three HPV tests vs. 11% with repeat cytology. However, the detection of < CIN2 (not indicating treatment) also increased with RR 2.11 (95% CI 2.01-2.21) for 14-type mRNA test, 1.35 (95% CI 1.29-1.41) for 5-type mRNA test, and 1.86 (95% CI 1.76-1.97) with HPV DNA test.

CONCLUSIONS

The choice of management strategy influences both the detection rate for severe lesions (CIN3+) and the proportion of women followed up for potentially insignificant findings.

A global epidemic increase of an HPV-induced tonsil and tongue base cancer - potential benefit from a pan-gender use of HPV vaccine

In 2007, human papillomavirus (HPV) type 16 was finally recognized as a risk factor, besides smoking and alcohol, for oropharyngeal squamous cell carcinoma (OPSCC), including tonsillar squamous cell carcinoma (TSCC), by the International Agency for Research against Cancer. Just before, in 2006, the Food and Drug Administration had approved Gardasil, the first vaccine against HPV16, 18, 6 and 11, for preventive vaccination women against cervical cancer. Concurrently, some Western countries, where smoking was decreasing, disclosed an epidemic increase in the incidence of OPSCC, especially of TSCC and base of tongue cancer (BOTSCC), together accounting for 80-90% of all OPSCCs, and mainly affecting men. The epidemic was later revealed to be due to a rise in HPV-positive cases, and scientists in the field suggested HPV vaccination also of boys. Globally, there are roughly 96 000 incident OPSCC cases/year of which 20-24% are caused by HPV, thereby accounting for around 22 000 OPSCC cases annually. Of these cases, 80-90% are due to HPV16 infection and would be prevented with the presently registered HPV vaccines. In Western countries, such as Sweden (with almost 400 TSCC and BOTSCC cases per year) and the United States, HPV prevalence in OPSCC is higher and around 70%. HPV vaccination of girls has been initiated in many countries, and the vaccines have been efficient and their side effects limited. HPV vaccination of boys has, however, been the exception, but should definitely not be delayed any further. It would benefit both girls and boys directly, and result in better and more robust herd immunity. Today, we have the possibility to eliminate several high-risk HPV types in the younger generations and avoid more than 600 000 cancer cases annually worldwide, and this possibility should be embraced by offering global pan-gender HPV vaccination.

Condom use to enhance regression of cervical intraepithelial neoplasia: study protocol for a randomized controlled trial

Background

Condom use can reduce the risk of infection by human papillomavirus (HPV). Furthermore, it has been suggested that condom use can increase the regression rate of cervical lesions. In Denmark, women with cervical intraepithelial neoplasia grade 2 (CIN2) and a future wish to conceive are not treated immediately but are followed up by a gynecologist about 6 months later. The aim of this project was to determine if advising women to have their male partners to use a condom during sexual intercourse in the follow-up period can increase the regression rate of CIN2.

Methods/design

This is a randomized clinical trial of women with CIN2. The intervention group was advised to use condoms between the date of diagnosis and the date of their follow-up visit. The control group received standard care. Cervical samples were tested for HPV. The primary endpoint will be the intention-to-treat analysis with the relative rate of CIN2 regression between the intervention group and the control group. Regression is defined as <CIN2 at the follow-up visit. In addition, a per-protocol analysis of the regression rate in women adhering to condom use compared with the control group will be performed. The secondary endpoint will be the HPV-clearance rate in the condom group.

Discussion

If condom use for 6 months can enhance the regression of cervical lesions, then more women can be spared conization. This is an efficient treatment of cervical lesions but is associated with an increased risk of preterm delivery.

Trial registration

ClinicalTrials.gov, NCT02907333. Registered on 14 September 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3564-4) contains supplementary material, which is available to authorized users.