This trial is designed to evaluate the safety, tolerability and immunogenicity of BLB-201 vaccine in infants (6-24 months of age) and children (18-59 months of age) who may or may not have had prior respiratory syncytial virus (RSV) infection. One (Day 1) or two doses (Day 1 and Day 57) of low (10^6 PFU) and high dosage (10^7 PFU) of BLB-201 will be evaluated.
This Phase 1/2a trial is a randomized, placebo-controlled trial to evaluate the safety, tolerability and immunogenicity of two ascending doses (10^6 PFU and 10^7 PFU) of intranasal BLB-201 (a recombinant parainfluenza virus type 5) administered in infants (6-24 months of age) and children (18-59 months of age) who may or may not have had prior respiratory syncytial virus (RSV) infection.