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.