Comparison of a single, high-dose vaccination regimen to the standard regimen for the investigational Japanese encephalitis vaccine, IC51: A randomized, observer-blind, controlled Phase 3 study

Abstract The standard administration of the investigational Japanese encephalitis vaccine IC51 is 2 doses of 6 μg with a 28-day interval. This study investigated the immunogenicity of a single-immunization, high-dose regimen (1 × 12 μg) compared to the 2-injection, standard regimen to determine the immune response that one, high-dose injection can confer. The single, high-dose regimen resulted in about 60% seroconversion rate (SCR) at 10 days after administration, but it did not reach the almost 100% SCR achieved by the 2-dose standard administration at Day 35. The standard regimen conferred essentially 100% seroconversion already 7 days after the second immunization.