A Retrospective Cohort Study of Young Women Spontaneously Choosing to Be Vaccinated against HPV: Outcomes from Their First Cervical Cancer Screening Test

Viruses. 2021 Mar 16;13(3):486. doi: 10.3390/v13030486.

Abstract

Background: Efficacy for cervical cancer prevention of opportunistic HPV vaccination in post-pubertal girls is lower than in 11-year-olds.

Methods: Women born between 1986 and 1992 vaccinated at 15-25 years of age (at least one dose of 4-valent HPV vaccine) and screened at 24-27 years of age were included. Frequency of opportunistic vaccination, overall and by birth cohort, was calculated; screening outcomes were compared between vaccinated and unvaccinated women.

Results: Overall, 4718 (4.9%) HPV-vaccinated, and 91,512 unvaccinated, women were studied. The frequency of vaccination increased by birth cohort, ranging between 1.8% and 9.8%; age at vaccination decreased progressively by birth cohort (p < 0.0001). Participation in screening was 60.8% among vaccinated, and 56.6% among unvaccinated, women (p < 0.0001). Detection rates (DR) for high-grade lesions were lower in vaccinated women (2.11‰ vs. 3.85‰ in unvaccinated, for CIN3+, p = 0.24; 0.0‰ vs. 0.22‰ for cancer). The DR of CIN3+ increased with age at vaccination, scoring respectively 0.0‰, 0.83‰, and 4.68‰ for women vaccinated when they were 15-16, 17-20, and 21-25 years old (p = 0.17).

Conclusions: In comparison to unvaccinated women, higher compliance with cervical cancer screening invitation and lower CIN3+ DR among vaccinated women was observed. Age at vaccination was inversely correlated to vaccination efficacy.

Keywords: CIN2; CIN3; HPV; age at vaccination; cancer; cervical cancer screening; prevention; prophylactic vaccination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Early Detection of Cancer
  • Female
  • Humans
  • Italy / epidemiology
  • Mass Screening
  • Papillomavirus Infections / prevention & control*
  • Papillomavirus Vaccines / administration & dosage*
  • Retrospective Studies
  • Uterine Cervical Neoplasms / prevention & control*
  • Young Adult

Substances

  • Papillomavirus Vaccines