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.
This study compares the immunogenity and safety of quadrivalent inactivated influenza vaccines. The experimental group receives the quadrivalent influenza vaccine developed by Sinovac Biotech Co., Ltd and the control group immunized with Vaxigrip Tetra™. The group has 1600 persons from general population 3 years and older. The design is double-blind and randomized. The primary outcome is the immunogenicity against the 4 strains of influenza included in both vaccines.