Prophylactic Efficacy of a Quadrivalent Human Papillomavirus (HPV) Vaccine in Women with Virological Evidence of HPV Infection
Background.
A quadrivalent (types 6, 11, 16, and 18) human papillomavirus (HPV) L1 virus‐like‐particle (VLP) vaccine has been shown to be 95%–100% effective in preventing cervical and genital disease related to HPV‐6, ‐11, ‐16, and ‐18 in 16–26‐year‐old women naive for HPV vaccine types. Because most women in the general population are sexually active, some will have already been infected with 
1 HPV vaccine types at the time vaccination is offered. Here, we assessed whether such infected women are protected against disease caused by the remaining HPV vaccine types.
Methods.Two randomized, placebo‐controlled trials of the quadrivalent (types 6, 11, 16, and 18) HPV vaccine enrolled 17,622 women without consideration of baseline HPV status. Among women infected with 1–3 HPV vaccine types at enrollment, efficacy against genital disease related to the HPV vaccine type or types for which subjects were naive was assessed.
Results.Vaccination was 100% effective (95% confidence interval [CI], 79%–100%) in preventing incident cervical intraepithelial neoplasia 2 or 3 or cervical adenocarcinoma in situ caused by the HPV type or types for which the women were negative at enrollment. Efficacy for preventing vulvar or vaginal HPV‐related lesions was 94% (95% CI, 81%–99%).
Conclusions.Among women positive for 1–3 HPV vaccine types before vaccination, the quadrivalent HPV vaccine protected against neoplasia caused by the remaining types. These results support vaccination of the general population without prescreening.
Received 19 December 2006; accepted 17 April 2007; electronically published 31 October 2007.
Cited by
Online publication date: 15-Jun-2009.
Online publication date: 1-Apr-2009.
Online publication date: 15-Mar-2009.
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Potential conflicts of interest: L.L.V., G.P., S.K.K., J.P., N.M., K.S., M.H.‐A., O.E.I., S.T., P.J.G., S.M., J.D., S.‐E.O., E.H.T., F.X.B., K.A.A., D.R.B., D.G.F., L.A.K., R.J.K., and E.R.M. have received honoraria from Merck Research Laboratories. These honoraria were given for consultation work and membership in the Phase III HPV Vaccine Steering and/or Registries Oversight Committees. R.J.K. is a member of the HPV Vaccine Program Pathology Panel; as such, he has been paid for his efforts in developing the Pathology Panel’s standard operating procedures and for its histopathological readings of biopsy slides. G.P., S.K.K., J.P., K.S., M.H.‐A., O.E.I., S.T., P.J.G., S.E.O., E.H.T., K.A.A., D.R.B., D.G.F., and L.A.K. led clinical sites that participated in the study. These investigators were compensated for all activities related to execution of the study. J.D., S.M., D.G.F., and N.M. have been given honoraria for lectureships on behalf of Merck’s HPV vaccine program. D.R.B. has been paid for consultations regarding the HPV vaccine program in men. D.G.F. has been paid for consultation regarding colposcopy quality control. K.A.A. is a member of Merck’s HPV Vaccine Obstetrics and Gynecology Advisory Board and, as such, receives honoraria for his consultative work.
Presented in part: European Research Organization on Genital Infection and Neoplasia Meeting, Paris, 23–26 April 2006 (abstract S11-2).
Financial support: Merck Research Laboratories (a division of Merck & Co., Inc.).
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(See the article by Kjær et al., on pages 1447–54, and the editorial commentary by Hildesheim and Herrero, on pages 1431–2.)
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Study group members are listed after the text.