Journal of Infectious Diseases
Volume 208 Issue 8 October 15, 2013
Immunogenicity of Quadrivalent HPV Vaccine Among Girls 11 to 13 Years of Age Vaccinated Using Alternative Dosing Schedules: Results 29 to 32 Months After Third Dose
D. Scott LaMontagne1,2, Vu Dinh Thiem3, Vu Minh Huong1,2, Yuxiao Tang1,2 and Kathleen M. Neuzil1,2
Background. Immune response to quadrivalent human papillomavirus (HPV) vaccine delivered at 0, 2, and 6 months in young adolescent females plateaus around 24 months after immunization. Antibody levels >24 months postvaccination using extended dosing schedules is unknown.
Methods. We conducted a follow-up immunogenicity study of adolescent girls in Vietnam who participated in a noninferiority trial to investigate whether immune responses using 3 alternative dosing schedules (0, 3, 9 months; 0, 6, 12 months; or 0, 12, 24 months) are noninferior to the standard schedule at >2 years after immunization.
Results. Quadrivalent HPV vaccine immunogenicity delivered on 3 alternative dosing schedules was noninferior for types 6, 11, 16, and 18 at 32 months post-dose 3 compared to the standard schedule. Pre-dose 3 antibody levels for the 0, 12, 24 month schedule were similar to those measured 32-months post-dose 3.
Conclusions. We found similar antibody concentrations ≥29 months after 3 doses of HPV vaccine regardless of dose-timing, and extended schedules do not produce inferior immune responses. Our findings also suggested that 2 doses of HPV vaccine delivered at 0 and 12 months might afford similar protection. Evidence supporting dosing flexibility could be important for national HPV vaccination policies.