Restrepo J.Herrera T.Samakoses R.Reina J.C.Pitisuttithum P.Ulied A.Bekker L.G.Moreira E.D.Olsson S.E.Block S.L.Hammes L.S.Laginha F.Ferenczy A.Kurman R.Ronnett B.M.Stoler M.Bautista O.Gallagher N.E.Salituro G.Ye M.Luxembourg A.Mahidol University2023-11-022023-11-022023-10-01Pediatrics Vol.152 No.4 (2023)00314005https://repository.li.mahidol.ac.th/handle/20.500.14594/90881BACKGROUND AND OBJECTIVES: The 9-valent human papillomavirus (9vHPV) vaccine Phase III immu-nogenicity study in 9- to 15-year-old boys and girls was extended to assess immunogenicity and effectiveness through 10 years after the last vaccine dose (NCT00943722). METHODS: Boys (n 5 301) and girls (n 5 971) who received three 9vHPV vaccine doses in the base study (day 1, months 2 and 6) enrolled in the extension. Serum was collected through month 126 for antibody assessments by competitive Luminex immunoassay and immunoglobulin G-Luminex immunoassay. For effectiveness analysis starting at age 16 years, genital swabs were collected (to assess HPV DNA by polymerase chain reaction) and external genital examinations conducted every 6 months. Primary analyses were conducted in per-protocol populations. RESULTS: Geometric mean antibody titers peaked around month 7, decreased sharply between months 7 and 12, then gradually through month 126. Seropositivity rates remained $81% by competitive Luminex immunoassay and $95% by immunoglobin G-Luminex immunoassay at month 126 for each 9vHPV vaccine type. After up to 11.0 (median 10.0) years of follow-up postdose 3, there were no cases of HPV6/11/16/18/31/33/45/52/58-related high-grade in-traepithelial neoplasia or condyloma in males or females. Incidence rates of HPV6/11/16/18/ 31/33/45/52/58-related 6-month persistent infection in males and females were low (54.6 and 52.4 per 10000 person-years, respectively) and within ranges expected in vaccinated cohorts, based on previous human papillomavirus vaccine efficacy trials. CONCLUSIONS: The 9vHPV vaccine demonstrated sustained immunogenicity and effectiveness through Ȉ10 years post 3 doses of 9vHPV vaccination of boys and girls aged 9 to 15 years.MedicineArticleSCOPUS10.1542/PEDS.2022-0609932-s2.0-851714181601098427537667847