Primary Immunization of Human Papillomavirus Vaccine in the Pediatric Population: What Is the Verdict Now?

The safety and efficacy of a 2-dose series for the human papillomavirus vaccines rather than a 3-dose series in older children has not been well defined. This article reviews the literature summarizing the use of all 3 HPV vaccines (2vHPV, 4vHPV, 9vHPV) as a 2-dose series for females and 4vHPV and 9vHPV for males younger than 15 years. Six prospective trials evaluating immunogenicity of a 2-dose series of 2vHPV and/or 4vHPV, as well as an ongoing prospective clinical trial for 9vHPV, are discussed. The 2-dose series with Gardasil 9® in both males and females ages 9 to 14 years appears to be the most widely accepted recommendation. The exact time schedule between the 2 vaccines varies among studies, but it seems that they should be separated by 6 to 12 months. Federal and world-wide organizations' (ie, Centers for Disease Control and Prevention, Food and Drug Administration, and World Health Organization) opinions and recommendations on the appropriate scheduling of the vaccines are also highlighted.