Abstract. Kang S, Kim KH, Kim YT, Kim YT, Kim JH, Song YS, Shin SH, Ryu HS, Han JW, Kang JH, Park SY. Safety and immunogenicity of a vaccine targeting human papillomavirus types 6, 11, 16 and 18: a randomized, placebo-controlled trial in 176 Korean subjects. Int J Gynecol Cancer 2008;18:1013-1019.Human papillomavirus (HPV) is a major causative agent of anogenital warts and a necessary cause of cervical cancer. This report will serve to assess the safety and immunogenicity of quadrivalent (types 6, 11, 16, and 18) HPV L1 virus-like particle (VLP) vaccine in the Korean population. We performed a randomized, doubleblind, placebo-controlled study in 176 volunteers aged 9-23 years. Using a 2:1 ratio for randomization, 117 women were assigned to quadrivalent HPV (20 lg type 6, 40 lg type 11, 40 lg type 16, and 20 lg type 18) vaccine and 59 women to placebo. Individuals received vaccine at day 1, month 2, and month 6 and provided blood samples for analysis at enrollment at month 7. Analyses were done as specified in the study protocol. Quadrivalent HPV vaccine was generally well tolerated, with no vaccine-related serious adverse experiences. Quadrivalent HPV vaccine induced seroconversion for each vaccine-related HPV type. At month 7, vaccineinduced type-specific antibody titer was high. In conclusion, administration of quadrivalent HPV VLP vaccine to Korean women aged 9-23 years was generally well tolerated and highly immunogenic.