Summary of results of microneutralizing antibody assay for B influenza strains. Note: Seroconversion rates (SCRs) of the microneutralizing antibody assay in all treatment groups. Neutralizing antibody responses to B/Malaysia and B/Jiangsu were measured before vaccination (Day 0, Pre) and 21 days post-vaccination (Day 21, Post). SCRs, defined as ≥4-fold increase in titer relative to the value noted at baseline, are presented with the associated 95% CI. Abbreviations: LD QIV-AS: low-dose adjuvanted quadrivalent influenza vaccine; LD TIV-AS: low-dose adjuvanted trivalent influenza vaccine; QIV: quadrivalent influenza vaccine; TIV: trivalent influenza vaccine.