IMPAACT 2021

IMPAACT 2021 is a double-blind, randomized, placebo-controlled trial that will evaluate the safety and immunogenicity of recombinant live-attenuated respiratory syncytial virus vaccines RSV ΔNS2/Δ1313/I1314L, RSV 6120 ΔNS2/1030s, RSV 276 or placebo in children confirmed to be RSV-seronegative within 42 days prior to study product administration. Approximately 160 healthy RSV-seronegative children ≥6 months (180 days) to <25 months (750 days) of age will be enrolled. Eligible children will receive a single dose of RSV ΔNS2/Δ1313/I1314L vaccine, RSV 6120 ΔNS2/1030s vaccine, RSV 276 vaccine or placebo intranasally at entry. Participants will be enrolled in the study outside of RSV season and will remain on study until they complete the post-RSV season visit between April 1st and April 30th in the calendar year following their enrollment.