Non-inferior antibody levels for HPV16/18 after extended two-dose schedules compared with a six-month interval: findings of a systematic review and meta-analysis Non-inferior antibody levels for HPV16/18 after extended two-dose schedules compared with a six-month interval: findings of a systematic review and meta-analysis
Protection after human papillomavirus (HPV) vaccination can be maximized by optimizing vaccination schedules. We systematically reviewed immunogenicity and effectiveness of HPV vaccines administered 6 months apart compared with longer intervals. Seroconversion to vaccine-type HPV was non-inferior for 12- compared with 6-month intervals, but inconclusive for comparison of 36-96 months with 6 months. A 12-month interval showed non-inferior (margin 0.5) vaccine-type HPV antibody responses compared with a 6-month interval. Compared to 6 months, an interval of 36-96 months resulted in non-inferior antibody responses for HPV6 and high-risk types HPV16 and 18, but did not lead to a non-inferior antibody response for HPV11 (GMR 0.63, 95% CI:0.41-0.97). Data on the effectiveness of extended two-dose schedules were limited. Our findings indicate that HPV immunization programs could adopt a 12-month interval instead of 6 months for increased flexibility without compromising immunogenicity. Further evaluation to confirm the immunogenicity and effectiveness of intervals beyond 12 months is warranted.
Protection after human papillomavirus (HPV) vaccination can be maximized by optimizing vaccination schedules. We systematically reviewed immunogenicity and effectiveness of HPV vaccines administered 6 months apart compared with longer intervals. Seroconversion to vaccine-type HPV was non-inferior for 12- compared with 6-month intervals, but inconclusive for comparison of 36-96 months with 6 months. A 12-month interval showed non-inferior (margin 0.5) vaccine-type HPV antibody responses compared with a 6-month interval. Compared to 6 months, an interval of 36-96 months resulted in non-inferior antibody responses for HPV6 and high-risk types HPV16 and 18, but did not lead to a non-inferior antibody response for HPV11 (GMR 0.63, 95% CI:0.41-0.97). Data on the effectiveness of extended two-dose schedules were limited. Our findings indicate that HPV immunization programs could adopt a 12-month interval instead of 6 months for increased flexibility without compromising immunogenicity. Further evaluation to confirm the immunogenicity and effectiveness of intervals beyond 12 months is warranted.