title: Epidemiologic Evaluation of Human Papillomavirus Type Competition and the Potential for Type Replacement Post-Vaccination.
abstract: BACKGROUND
  Millions of women have been vaccinated with one of two first-generation human papillomavirus (HPV) vaccines. Both vaccines remain in use and target two oncogenic types (HPVs 16 and 18); however, if these types naturally compete with others that are not targeted, type replacement may occur following reductions in the circulating prevalence of targeted types. To explore the potential for type replacement, we evaluated natural HPV type competition in unvaccinated females.
  
  
  METHODS
  Valid HPV DNA typing information was available from five epidemiological studies conducted in Canada and Brazil (n = 14,685; enrollment across studies took place between1993 and 2010), which used similar consensus-primer PCR assays, capable of detecting up to 40 HPV types. A total of 38,088 cervicovaginal specimens were available for inclusion in our analyses evaluating HPV type-type interactions involving vaccine-targeted types (6, 11, 16, and 18), and infection with each of the other HPV types.
  
  
  RESULTS
  Across the studies, the average age of participants ranged from 21.0 to 43.7 years. HPV16 was the most common type (prevalence range: 1.0% to 13.8%), and in general HPV types were more likely to be detected as part of a multiple infection than as single infections. In our analyses focusing on each of the vaccine-targeted HPV types separately, many significant positive associations were observed (particularly involving HPV16); however, we did not observe any statistically significant negative associations.
  
  
  CONCLUSIONS
  Our findings suggest that natural HPV type competition does not exist, and that type replacement is unlikely to occur in vaccinated populations.
authors.affiliation: McGill University, Department of Oncology, Montreal, Québec, Canada.|McGill University, Department of Epidemiology, Biostatistics, and Occupational Health, Montreal, Québec, Canada.|National Cancer Institute, Division of Cancer Epidemiology and Genetics, Infections and Immunoepidemiology Branch, Rockville, Maryland, United States of America.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Tota
authors.affiliation: McGill University, Department of Oncology, Montreal, Québec, Canada.
authors.forename: Mengzhu
authors.initials: M
authors.lastname: Jiang
authors.affiliation: McGill University, Department of Oncology, Montreal, Québec, Canada.
authors.forename: Agnihotram V
authors.initials: AV
authors.lastname: Ramanakumar
authors.affiliation: McMaster University, Department of Clinical Epidemiology and Biostatistics, Hamilton, Ontario, Canada.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Walter
authors.affiliation: McGill University, Department of Epidemiology, Biostatistics, and Occupational Health, Montreal, Québec, Canada.
authors.forename: Jay S
authors.initials: JS
authors.lastname: Kaufman
authors.affiliation: Université de Montréal, Département de Microbiologie et Infectiologie, Montreal, Québec, Canada.|Université de Montréal Hospital Research Centre, Montreal, Québec, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Coutlée
authors.affiliation: Queen's University, Department of Public Health Sciences, Kingston, Ontario, Canada.
authors.forename: Harriet
authors.initials: H
authors.lastname: Richardson
authors.affiliation: McGill University, Department of Oncology, Montreal, Québec, Canada.|St. Michael's Hospital, Department of Family and Community Medicine and Centre for Research on Inner City Health, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada.
authors.forename: Ann N
authors.initials: AN
authors.lastname: Burchell
authors.affiliation: Université de Montréal Hospital Research Centre, Montreal, Québec, Canada.|Université de Montréal, Département de médecine sociale et préventive, Montreal, Québec, Canada.
authors.forename: Anita
authors.initials: A
authors.lastname: Koushik
authors.affiliation: Université de Montréal Hospital Research Centre, Montreal, Québec, Canada.|Université de Montréal, Département d'obstétrique-gynécologie et Médecine Sociale et Préventive, Montreal, Québec, Canada.
authors.forename: Marie Hélène
authors.initials: MH
authors.lastname: Mayrand
authors.affiliation: Universidade de São Paulo, Department of Radiology and Oncology, School of Medicine, São Paulo, Brazil.
authors.forename: Luisa L
authors.initials: LL
authors.lastname: Villa
authors.affiliation: McGill University, Department of Oncology, Montreal, Québec, Canada.|McGill University, Department of Epidemiology, Biostatistics, and Occupational Health, Montreal, Québec, Canada.
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Franco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D002584:Cervix Uteri / Q000821:virology; D060085:Coinfection / Q000453:epidemiology / Q000821:virology; D004279:DNA, Viral / Q000032:analysis / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D027383:Papillomaviridae / Q000235:genetics* / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D055815:Young Adult
chemical_list: D004279:DNA, Viral