Long-term follow-up observation of the safety, immunogenicity, and effectiveness of Gardasil™ in adult women

PLoS One. 2013 Dec 31;8(12):e83431. doi: 10.1371/journal.pone.0083431. eCollection 2013.


Background: Previous analyses from a randomized trial in women aged 24-45 have shown the quadrivalent HPV vaccine to be efficacious in the prevention of infection, cervical intraepithelial neoplasia (CIN) and external genital lesions (EGL) related to HPV 6/11/16/18 through 4 years. In this report we present long term follow-up data on the efficacy, safety and immunogenicity of the quadrivalent HPV vaccine in adult women.

Methods: Follow-up data are from a study being conducted in 5 sites in Colombia designed to evaluate the long-term immunogenicity, effectiveness, and safety of the qHPV vaccine in women who were vaccinated at 24 to 45 years of age (in the original vaccine group during the base study [n = 684]) or 29 to 50 years of age (in the original placebo group during the base study [n = 651]). This analysis summarizes data collected as of the year 6 post-vaccination visit relative to day 1 of the base study (median follow-up of 6.26 years) from both the original base study and the Colombian follow-up.

Results: There were no cases of HPV 6/11/16/18-related CIN or EGL during the extended follow-up phase in the per-protocol population. Immunogenicity persists against vaccine-related HPV types, and no evidence of HPV type replacement has been observed. No new serious adverse experiences have been reported.

Conclusions: Vaccination with qHPV vaccine provides generally safe and effective protection from HPV 6-, 11-, 16-, and 18-related genital warts and cervical dysplasia through 6 years following administration to 24-45 year-old women.

Trial registration: Clinicaltrials.govNCT00090220.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Colombia
  • Condylomata Acuminata / prevention & control
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18
  • Human papillomavirus 11 / immunology
  • Human papillomavirus 16 / immunology
  • Human papillomavirus 18 / immunology
  • Human papillomavirus 6 / immunology
  • Humans
  • Middle Aged
  • Papillomavirus Infections / prevention & control
  • Papillomavirus Vaccines / adverse effects
  • Papillomavirus Vaccines / immunology
  • Papillomavirus Vaccines / therapeutic use*
  • Pregnancy
  • Safety
  • Treatment Outcome
  • Uterine Cervical Dysplasia / prevention & control
  • Uterine Cervical Neoplasms / prevention & control
  • Young Adult


  • Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18
  • Papillomavirus Vaccines

Associated data

  • ClinicalTrials.gov/NCT00090220

Grants and funding

The study was designed and funded by the sponsor (Merck & Co, Inc.) in collaboration with external investigators and an external data and safety monitoring board. The sponsor collated the data, monitored the conduct of the study, performed the statistical analysis and coordinated the writing of the manuscript with all authors. The authors were actively involved in the collection, analysis or interpretation of the data, the revising of the manuscript for intellectual content, and approved the final manuscript. All authors had access to data and took part in the decision on where to submit the paper for publication.