A randomized, double-blind, non-inferiority trial comparing the immunogenicity and safety of two seasonal inactivated influenza vaccines in adults

Background: To enhance the production and availability of influenza vaccines in different regions of the world is paramount to mitigate the global burden of this disease. Instituto Butantan developed and man-ufactured an embryonated egg-based inactivated split-virion trivalent seasonal influenza vaccine as part of a technology transfer partnership with Sanofi Pasteur.Methods: This is a phase IV, randomized, double-blind, active-controlled, multicenter clinical trial includ-ing adults 18-60 and > 60 years recruited during the 2019 southern hemisphere influenza season. Subjects were randomized 1:1 to receive either the Sanofi Pasteur Trivalent Seasonal Influenza Vaccine (SP-TIV) or Instituto Butantan Trivalent Seasonal Influenza Vaccine (IB-TIV). Hemagglutinin inhibition antibody titers were assessed pre-vaccination and 21 days post-vaccination.Results: 624 participants were randomized and vaccinated. In both intention-to-treat and per-protocol analysis, non-inferiority of the SP-TIV versus IB-TIV was demonstrated for the three influenza strains. In the per-protocol analysis, the SP-GMT/IB-GMT ratios for H1N1, H3N2, and B were 0.9 (95%CI, 0.7- 1.1), 1.2 (95%CI, 1.0-1.4), and 1.1 (95%CI, 0.9-1.3), respectively. Across vaccination groups, the most com-mon adverse reactions (AR) were limited to the injection-site, including pain and tenderness. The major-ity of the ARs were graded 1 and/or 2 and lasted less than one day. No serious adverse reaction was observed.Conclusion: This study demonstrated the non-inferiority of the immunogenicity of a single-dose of Instituto Butantan versus a single dose of the Sanofi Pasteur Seasonal Trivalent Influenza Vaccine in adults. Both vaccines were well tolerated and presented similar safety profiles.(c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates that the seasonal influenza vaccine developed by Instituto Butantan is comparable to the one developed by Sanofi Pasteur in terms of immunogenicity and safety.