Given the likelihood that the Cervarix vaccine would be approved, the Direction générale de la santé publique (MSSS) submitted a request to the Institut national de santé publique du Québec (INSPQ) on December 19, 2007, asking the latter to produce an advice with respect to the following question: “Do the two HPV vaccines have an equivalent ability to achieve the stated goal of the immunization pr [...] The primary criteria for determining the efficacy of HPV vaccines are their impact on: • the incidence of persistent infections; • the incidence of CIN2, CIN3 and adenocarcinoma in situ. [...] Institut national de santé publique du Québec 3 Advice of the Institut national de santé publique du Québec on human papillomavirus vaccines In the case of the GardasilTM vaccine, two other indicators were measured: • impact on the incidence of condyloma acuminatum (described in section 3); and • impact on the incidence of vulvar and vaginal cancer precursors. [...] Aspects that differed between the two vaccines included: the criteria used to select subjects for the clinical trials and to define a persistent infection, the tests used and their frequency, the method employed to interpret and present the results, the intervals between vaccinations, and the analyses carried out. [...] A reduction of more than 90% in the rate of persistent infections and of almost 100% in the number of high-grade cervical lesions associated with the HPV types included in the two vaccines were observed over a period of 5 to 5.5 years after vaccination10,11,19-21.