Chimeric parainfluenza viruses (PIVs) are provided that incorporate a PIV vector
genome or antigenome modified to
encode a chimeric
glycoprotein incorporating one or more
heterologous antigenic domains, fragments, or epitopes of a second, antigenically distinct HPIV. These chimeric viruses are infectious and attenuated in humans and other mammals and are useful in vaccine formulations for eliciting an immune responses against one or more PIVs, and, optionally against respiratory syncytial
virus (RSV). Also provided are isolated
polynucleotide molecules and vectors incorporating a chimeric PIV
genome or antigenome which includes a HPIV vector
genome or antigenome combined or integrated with one or more
heterologous genome segment(s) encoding one or more antigenic
determinant(s) of a
heterologous PIV to
encode a chimeric
glycoprotein. In preferred aspects of the invention, the
chimeric virus is attenuated for use as a vaccine agent by additional mutations or
nucleotide modifications introduced into the chimeric genome or antigenome.