Background: MenACWY-CRM (Menveo (R), Novartis Vaccines, Siena, Italy) is a quadrivalent meningococcal conjugate vaccine developed to help prevent invasive meningococcal disease caused by Neisseria meningitidis serogroups A, C, W, and Y. It is approved within the European Union in persons >2 years of age and in persons from 2 months to 55 years of age in the United States, among other countries. Little is known about the immunogenicity and safety of this vaccine in Taiwanese children >2 years and adolescents. This study assessed the immunogenicity and safety of a single injection of MenACWY-CRM vaccine in Taiwanese subjects aged 2-18 years old. Methods: In this phase III, multicentre, open-label study 341 subjects received one dose of MenACWY-CRM. Immunogenicity measures were rates of seroresponse (defined as the proportion of subjects with a postvaccination hSBA >= 1:8 if the prevaccination (baseline) titre was <1:4, or at least a fourfold higher hSBA Litre than baseline if the prevaccination titre was >= 1:4), percentages of subjects with serum bactericidal activity (hSBA) >= 1:8 for serogroups A, C, W and Y and hSBA geometric mean titres (GMTs). Local and systemic reactions and all adverse events (AEs) were recorded for 7 days, and medically attended AEs for 1 month post-vaccination. Results: Seroresponse rates after MenACWY-CRM vaccination at Day 29 for the serogroups A, C, W, and Y were 83%, 93%, 50%, and 65%, respectively. At Day 29 the percentages of subjects with hSBA >= 1:8 against all four serogroups A, C, W and Y were: 83%, 96%, 96% and 82%, respectively. GMTs against all serogroups rose by >= 7-fold from baseline to Day 29. The vaccine was well tolerated. Conclusions:A single dose of MenACWY-CRM demonstrated a robust immune response, and an acceptable safety profile in Taiwanese children and adolescents. (C) 2014 Elsevier Ltd. All rights reserved.