Phase Ⅲ, Clinical Trial to Compare an Inactivated Quadrivalent Influenza Vaccine and a Licensed Vaccine in Chile

The study is designed to evaluate the immunogenicity of the quadrivalent inactivated-virus influenza vaccine developed by Sinovac Biotech Co., Ltd against Vaxigrip Tetra™. The population included in the study is healthy subjects 3 years and older, being 800 individuals 10 years old or less and 800 over 18 years, randomized 1:1 to experimental vaccine or Vaxigrip Tetra™. Volunteers 8 years old or less, without history of previous influenza infection will receive 2 doses of vaccine, al other individuals will receipt 1 dose of vaccine. Immunogenicity will be assessed one month after the last dose of vaccine, humoral responses will be determined for all patients meanwhile ome subgroup of patients will have a determination of cellular immunity also. Subjects will be follow up for one month, adverse events will be assessed during this time.