Summary of RSV Ab and CMI response rates.
A positive seroresponse was defined as ≥1.5-fold rise from baseline for RSV F IgG and IgG. A positive nasal IgA Ab response was defined as ≥2-fold rise over baseline. CMI response was defined as >0.1% rise of sum of individual T cell secreting >1 cytokine after subtraction of baseline (before vaccination). CTL response was defined by the change in IFN-γ–producing CD8All participants were also seropositive for RSV F–specific serum IgA and IgG Abs at baseline (Overall, the results suggested that BLB201 boosted RSV-specific serum Ab levels in young adults (33 to 59 years old) and elderly (61 to 75 years old), although with greater magnitude in adults versus elderly. The fold increases in RSV-specific Ab titers inversely correlated with baseline titers. It is possible that the higher baseline titers were close to maximum levels.We next examined vector-specific immune responses. For PIV5 nAbs at baseline, 15 of 29 (52%) participants were seropositive as defined by a titer of 1:10 (