ABSTRACT
Objective: Human papillomavirus (HPV) vaccination was introduced in Japan in April 2013, as a national immunization program for girls aged 12–16 years, after an initial introduction in 2010 as a public-aid program for girls aged 13–16 years. The Yuri-Honjo district had the highest vaccine coverage among women aged 17–51 years in 2017, due to the original public-aid program. The aim of this study was to evaluate the differences in the vaccine types of HPV16/18 infections between 2008–2012 (pre-vaccine era) and 2013–2017 (vaccine era).Materials and Methods: We evaluated whether HPV vaccination was associated with a decrease in the prevalence of HPV16/18 and high-risk HPV and the incidence of HPV-associated cervical lesions. A total of 1,342 women aged 18–49 years, covering both the pre-vaccine and vaccine eras, who visited Yuri Kumiai General Hospital and underwent HPV genotype tests from June 2008 to December 2017 were compared.Results: Among women aged 18–24 years with higher vaccine coverage (68.2%), the prevalence of HPV16/18 and high-risk HPV decreased from 36.7% and 69.4%, respectively, in the pre-vaccine era to 5.8% and 50.0%, respectively, in the vaccine era (p=0.00013 and p=0.047, respectively). Among those with cervical intraepithelial neoplasia grade 2− and grade 2+, HPV16/18 prevalence decreased from 30.0% to 2.7% (p=0.0018) and from 81.8% to 36.4% (p=0.030), respectively. In this age group, the rate of HPV16/18 positivity decreased significantly. Among age groups with lower vaccine coverage, HPV prevalence did not significantly differ between the two eras.Conclusion: The prevalence of HPV16/18 and high-risk HPV significantly decreased in women aged 18–24 years, most of whom were vaccinated. HPV vaccination effectively reduced the prevalence of HPV16/18 infections in the Yuri-Honjo district.
ABSTRACT
This study sought to demonstrate the benefits of conducting cervical cytology and human papillomavirus (HPV) testing in our cervical cancer screening program and was conducted between April 2012 and March 2017 in the Yuri-Honjo district of Akita Prefecture. A total of 3581 women aged 20-49 years underwent this combined screening for 5 years. Of these, 10.3% (369/3581) tested positive for HPV, and 433 women were initially diagnosed as positive for atypical squamous cells of undetermined significance and/or positive for HPV. Of those, 342 women (79.0%) underwent cervical biopsy, among whom 62 (18.1%) were diagnosed as positive for cervical intraepithelial neoplasia (CIN)2+. Of 204 women who were positive for HPV but showed no abnormalities in cytology, 24 women (11.8%) were positive for CIN2+ and 6 women were positive for CIN3+. Conventional cytology (Pap test) detected only 0.58% of the examinees positive for CIN2+ in Akita Prefecture, whereas our combined screening involving a Pap test and HPV testing detected 1.73% of the examinees (P<0.0001). We recommend HPV testing be used in combination with the Pap test to improve cervical cancer screening and accurately identify CIN2/3 disease.