Immunogenicity of the Booster Dose of Two MenC Vaccines

Inclusion Criteria: * Healthy toddlers of both sexes * Toddlers of 14 to 19 months of age (including the day that the toddler is 14 and the day before he is 19 months of age) * Children previously vaccinated with two doses of polysaccharide meningococcal C vaccine conjugated to tetanus toxoid or three doses of polysaccharide meningococcal C conjugated to CRM197 before 7 month of age. * Informed consent signed by one or both parents who are adequately informed about the study. Exclusion Criteria: * Toddlers with severe diseases or axilar temperature ≥ 38,0ºC at inclusion time * Toddlers with severe chronic diseases * Toddlers who have received any other vaccine within the last month or with a programmed vaccination within the 28 subsequent days after the administration of the vaccine of study. * Toddlers with clinical or bacteriological diagnosis of previous meningococcal disease. * Toddlers with hypersensitivity to any of the components of the vaccines to study or antibiotics used during the manufacturing process that could be present as non- detectable traces (streptomycin, neomycin, polymyxin B). * Toddlers with personal history of convulsions. * Toddlers with known bleeding disorder no controlled * Toddlers with known congenital or acquired immunodeficiency * Toddlers who are receiving or have been received any treatment that could change the immune response (administration of intravenous immunoglobulin, systemic corticosteroids or haemoderivates) within the 3 previous months. * A toddler that under investigator opinion is probable to be lost during the follow-up * A toddler that is currently included or is planned to be included in any other clinical trial. * A toddler that under investigator opinion must not be included in the study due to other medical or social reasons.