HPV16/18 prevalence in high-grade cervical lesions in an Australian population offered catch-up HPV vaccination

OBJECTIVES

Using laser capture microdissection (LCM) and sensitive human papillomavirus (HPV) genotyping, we aimed to determine the distribution of vaccine-preventable types in cervical intraepithelial neoplasia grade 3 (CIN3) lesions and adenocarcinoma in situ (AIS) in young women in Victoria, Australia, offered catch-up HPV vaccination, as a baseline for ongoing vaccine impact monitoring. We also compared findings with available pre-vaccination estimates from women with HPV detected on concurrently-collected cytology samples.

METHODS

Consecutive histologically-confirmed CIN3/AIS biopsies were collected between May 2011 and December 2014 from vaccine-eligible women (born after 30th June 1981). Genotypes present in whole tissue sections (WTS) were determined by a sensitive reverse hybridisation assay; RHA kit HPV SPF10-LiPA25, v1 (Labo Bio-medical Products). Where multiple genotypes were detected, lesions were isolated using LCM and genotyped. Cervical cytology samples from a pre-vaccine cohort had been previously collected and genotyped using HPV Linear Array HPV Genotyping Test (Roche Diagnostics). Mixed-genotype detections in this cohort were resolved to single-lesion-attributable genotypes using hierarchical attribution.

RESULTS

Overall, 213 and 530 cases were included from pre- and post-vaccine time-periods, respectively. In 18-25 year-olds, the proportion of HPV16/18-positive CIN3/AIS decreased significantly over time from 69% in 2001-2005 (pre-vaccine), to 62% in 2011-2012 (post-vaccine), to 47% in 2013-2014 (p-trend = 0.004). There was no significant change in HPV16/18 in 26-32 year-olds (p-trend = 0.15). In 2013/14, nonavalent vaccine types accounted for 80% of CIN3/AIS in 18-25 year old women and 90% in 26-32 year old women.

CONCLUSION

Four to 8 years following implementation of HPV vaccination in Australia, approximately 70% of CIN3/AIS in young women was due to HPV16/18. Our data, despite some limitations due to change in methods between pre- and post-vaccine periods, suggests that for vaccine-eligible women aged 18-25 at the time of biopsy, the proportion of HPV16/18-attributable CIN3/AIS lesions is significantly declining post-vaccination.

Factors influencing intention to obtain the HPV vaccine in South East Asian and Western Pacific regions: A systematic review and meta-analysis

Since licensing in 2006, there has been poor uptake of the HPV vaccine among the targeted population in the South East Asia Region (SEAR) and Western Pacific Region (WPR). A systematic review was conducted to identify the studies exploring the relationship between factors and intention for HPV vaccination among women in SEAR and WPR countries. Nineteen studies were identified as suitable for qualitative synthesis, and three as suitable for meta-analysis. Most women had a positive intention to have an HPV vaccine (range 57%-85%). Having a positive intention to vaccinate was significantly higher among women not aware of HPV infection (OR: 1.34, 95% CI: 1.02-1.76) and HPV vaccine (OR: 1.57, 95% CI: 1.26-1.96). Lower knowledge level and less confidence in safety and efficacy of the vaccine, negatively affected intention to vaccinate. Perceiving the vaccine to be expensive, low perception of contracting HPV infection and cervical cancer, and lack of concrete recommendations from healthcare providers also negatively affected intention to vaccinate. This review suggests the decision-making processes of women in SEAR and WPR is influenced by the cost of vaccination, perceived efficacy and safety of vaccine, provision of information on vaccination, and the awareness about HPV infection and the HPV vaccine.

Factors involved in human papillomavirus (HPV) vaccine hesitancy among women in the South-East Asian Region (SEAR) and Western Pacific Region (WPR): A scoping review

A scoping review was performed to identify factors that may lead to human papillomavirus (HPV) vaccine hesitancy among women in low- and middle-income countries in South East Asian Region (SEAR) and Western Pacific Region (WPR). A systematic search of English and non-English articles using Pubmed, EMBASE, PsycINFO, Cochrane, MEDLINE, and CINAHL plus was conducted. Only 63 studies conducted in SEAR and WPR were included from inception until December 2016. Results of these studies have shown that poor awareness and knowledge of practices on cervical cancer prevention was evident in both SEAR and WPR. Concerns on safety and efficacy of the vaccine, and costs in getting vaccinated were significant barriers. Most women stated that they needed more information, and strongly welcomed a physician's recommendation in both geographical regions. Women also felt they have a low risk of acquiring HPV infection and cervical cancer. Most women in SEAR and WPR were unable to decide on whether to accept HPV vaccination.

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.