Vaccines (Jan 2022)

Changes in HPV16/18 Prevalence among Unvaccinated Women with Cervical Intraepithelial Neoplasia in Japan: Assessment of Herd Effects following the HPV Vaccination Program

  • Mamiko Onuki,
  • Kasumi Yamamoto,
  • Hideaki Yahata,
  • Hiroyuki Kanao,
  • Koji Horie,
  • Katsuyuki Konnai,
  • Ai Nio,
  • Kazuhiro Takehara,
  • Shoji Kamiura,
  • Naotake Tsuda,
  • Yuji Takei,
  • Shogo Shigeta,
  • Hidekatsu Nakai,
  • Hiroyuki Yoshida,
  • Takeshi Motohara,
  • Tatsuya Kato,
  • Keiichiro Nakamura,
  • Junzo Hamanishi,
  • Nobutaka Tasaka,
  • Mitsuya Ishikawa,
  • Nobuhiro Kado,
  • Yusuke Taira,
  • Mayuyo Mori,
  • Takashi Iwata,
  • Fumiaki Takahashi,
  • Iwao Kukimoto,
  • Hiroyuki Yoshikawa,
  • Nobuo Yaegashi,
  • Koji Matsumoto,
  • for the MINT Study Group

DOI
https://doi.org/10.3390/vaccines10020188
Journal volume & issue
Vol. 10, no. 2
p. 188

Abstract

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Since the human papillomavirus (HPV) vaccination program for Japanese girls aged 12–16 years began in 2010, vaccination uptake has been low in women born before 1993 but high (approximately 70%) in those born during 1994–1999. We previously compared the prevalence of vaccine types HPV16 and HPV18 in cervical intraepithelial neoplasia grade 1–3 (CIN1–3) or adenocarcinoma in situ (AIS) between vaccinated and unvaccinated cohorts and found direct protection effects among vaccinated women in Japan. In this study, we focused on changes in HPV16/18 prevalence among “unvaccinated” cohorts with CIN/AIS. We analyzed HPV16/18 prevalence among 5051 unvaccinated women aged trend = 0.03) and CIN2–3/AIS (62.5–36.4%, Ptrend = 0.07) among women aged p = 0.04). Significant reduction in HPV16/18 prevalence among young unvaccinated women with CIN1 and CIN2–3/AIS suggests herd effects of HPV vaccination in Japan.

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