Reduction in HPV 16/18 prevalence among young women following HPV vaccine introduction in a highly vaccinated district, Japan, 2008–2017

Akihiro Karube; Fumiko Saito; Enami Nakamura; Akihiro Shitara; Natsuki Ono; Megumi Konno; Daisuke Tamura; Daisuke Nagao

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Reduction in HPV 16/18 prevalence among young women following HPV vaccine introduction in a highly vaccinated district, Japan, 2008–2017

VernacularTitle:Reduction in HPV 16/18 prevalence among young women following HPV vaccine introduction in a highly vaccinated district, Japan, 2008–2017
Author: Akihiro KARUBE ¹ ; Fumiko SAITO ¹ ; Enami NAKAMURA ¹ ; Akihiro SHITARA ² ; Natsuki ONO ² ; Megumi KONNO ² ; Daisuke TAMURA ² ; Daisuke NAGAO ³
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1. Department of Obstetrics and Gynecology, Yuri Kumiai General Hospital, Japan
2. Department of Obstetrics and Gynecology, Akita University School of Medicine, Japan
3. Department of Obstetrics and Gynecology, Omagari Kosei Medical Center, Japan
Keywords: cervical cancer; HPV16/18; high risk HPV; HPV vaccine; young women
From:Journal of Rural Medicine 2019;14(1):48-57
CountryJapan
Language:English
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.