Randomized controlled trial of two dosing schedules for human papillomavirus vaccination among college age males

Abstract

Background: Quadrivalent human papillomavirus (HPV) vaccine, for protection against sexually transmitted HPV infection, is licensed for females and males 9-26 years on a 3-dose schedule (0, 2, and 6 months; Standard schedule). Vaccine uptake has been low and catch-up vaccination of older adolescents using an alternate dosing schedule may increase coverage. This study tested the non-inferiority of the immunogenicity of an alternate dosing schedule (0, 2, 12 months) among college age males.

Methods: 220 18-25 year old males were randomly assigned to Standard or Alternate schedules. Blood samples were drawn immediately before Dose 1 and 2-6 weeks after Dose 3 and analyzed for antibody titers using a Luminex immunoassay. A value <1.5 for the upper 95% confidence interval (CI) bound of the Standard to Alternate schedule geometric mean titer (GMT) ratio was deemed non-inferior.

Results: Participants averaged 21.3 years old; 19.1% were non-white; completion rate was 93%. The anti-HPV titers for the Alternate schedule group were non-inferior to those of Standard schedule group for all four HPV vaccine virus types. Our results also demonstrated superiority of the Alternate schedule group for all four HPV vaccine virus types.

Conclusion: A delayed third dose at 12 months is immunologically non-inferior and superior for four HPV virus types. Using an alternate dosing schedule offers more flexibility to receive the 3-dose HPV vaccine and may result in higher vaccination rates among college-age males.

Trial registration: ClinicalTrials.gov NCT01184079.

Keywords: HPV vaccine; Human papillomavirus; Immunization; Non-inferiority.

Conflict of interest statement

Conflict of Interest

The authors have no other conflicts to report regarding HPV vaccine.

Copyright © 2013 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Recruitment, Enrollment, Treatment Allocation, Follow-up, Per Protocol Analysis

Figure 2

Reverse Cumulative Distribution Curves of Log Transformed Antibody Titers by HPV type Solid line = anti-HPV for Dose 3 at 6 months (Standard schedule); dashed line = anti- HPV for Dose 3 at 12 months (Alternate schedule); mM unit/mL: milliMerck unit/mL.