Safety and immunogenicity of 3 seasonal trivalent influenza vaccines in the Chinese military

Influenza, caused by the influenza virus, is a contagious acute viral respiratory disease with a high incidence rate and wide and rapid spread. Influenza-related morbidity, mortality, and hospitalization rates remain high and are increasing continuously in high-risk groups, with a significant impact on human health and the economy. In order to evaluate the immunogenicity of 3 seasonal trivalent influenza vaccines in Chinese military, we conducted this field trial. We assessed the safety and immunogenicity of 3 seasonal trivalent influenza vaccines(TIVs)manufactured by GlaxoSmithKline(GSK), Beijing Sinovac Biotech (Sinovac), and Shenzhen Sanofi Pasteur (Pasteur) in healthy Chinese servicemen. We used theimported GSKTIV as the control, comparing it with the 2 domestic TIVs in a 1:1:1randomized, double-blind, controlled trial in a military command in Beijing. Healthy individuals, aged between 18 and 34 years, who had not received any influenza vaccine in the preceding3 years were enrolled and administered one dose of a TIV. Safety data were collected throughout the whole study (day 0 to day 30). Blood samples were collected to assess the subjects' immunogenicity before vaccination and 21 d after vaccination. In total, 292 subjects enrolled in the study. Twelve participants (4.1%) reported 12 adverse events. The incidence of adverse events was 1%, 5%, and7% for the GSK, Sinovac, and Pasteur TIVs, respectively. The reported injection-site reaction frequencies were similar for all 3 TIVs (p = 0.217). However, the proportion of systemic reactions was higher after the GSKTIV than after the Pasteur or Sinovac TIV (7.1% vs 3.1% or1%, respectively; p = 0.020). Three TIVs satisfied both the European and US Food and Drug Administration criteria for H1N1–179, H1N1–74, H3N2, and B strains based on the post vaccination sero-protection, the sero-conversion rate, and the geometric mean titer ratio. The Sinovac TIV, Pasteur TIV, and GSK TIV were well tolerated and immunogenic in healthy servicemen in the military. There was no significant difference in the immunogenicity of these 3 vaccines.