The present invention relates to methods of inducing a safe immune response against respiratory syncytial virus (RSV) in a human subject in need thereof, comprising administering to the subject a composition comprising recombinant adenovirus comprising nucleic acid encoding an RSV Fusion (F) protein comprising the amino acid sequence of SEQ ID NO: 1, and a pharmaceutically acceptable carrier, in a total dose of from about 1x1010 to about 2x10 11 viral particles (vp).