Abstract
BACKGROUND The immunogenicity of current influenza vaccines needs improvement. Inactivated influenza and COVID-19 mRNA vaccines can be coadministered, but randomized controlled trial data are lacking on whether the 2 vaccines are more immunogenic if given in the same arm or opposite arms. Murine studies suggest mRNA vaccines can adjuvant influenza vaccines when coformulated and codelivered.METHODS We randomly assigned 56 adults to receive the Afluria quadrivalent inactivated influenza and Moderna monovalent SARS-CoV-2 XBB.1.5 mRNA vaccines, either in opposite arms or both in the same arm at the same site. The primary endpoint was the difference in median combined serum hemagglutination inhibition titer to the H1, H3, and B-Vic vaccine influenza strains after vaccination.RESULTS We found no significant difference in hemagglutination inhibition antibody levels between the groups (P = 0.30), with the same-arm group having a 1.26-fold higher titer than the opposite-arm group. There were no differences in analyses of antibodies against individual influenza strains or in nasal or saliva antibody levels. While both binding and neutralizing antibody titers against SARS-CoV-2 were not significantly different between groups postvaccination, there was a higher fold-change in BA.5 and ancestral strain neutralizing antibodies in the opposite-arm group.CONCLUSION Influenza vaccination is equivalently immunogenic if given in the same arm or opposite arms as the SARS-CoV-2 vaccine, but it may be preferable to administer the SARS-CoV-2 vaccine at a different site from influenza vaccines.TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry ACTRN12624000445572.FUNDING Australian National Health and Medical Research Council, Australian Medical Research Future Fund, and National Institutes of Health (UH2AI176172).
Authors
Wen Shi Lee, Kevin J. Selva, Jennifer Audsley, Helen E. Kent, Arnold Reynaldi, Timothy E. Schlub, Deborah Cromer, David S. Khoury, Heidi Peck, Malet Aban, Mai Ngoc Vu, Ming Z.M. Zheng, Amy W. Chung, Marios Koutsakos, Hyon-Xhi Tan, Adam K. Wheatley, Jennifer A. Juno, Steven Rockman, Miles P. Davenport, Ian Barr, Stephen J. Kent
Adverse events reported for the total cohort and by allocation
