Recombinant respiratory syncytial virus (RSV) having the position of genes
shifted within the genome or antigenome of the recombinant virus are
infectious and attenuated in humans and other mammals. Gene shifted RSV
are constructed by insertion, deletion or rearrangement of genes or
genome segments within the recombinant genome or antigenome and are
useful in vaccine formulations for eliciting an anti-RSV immune response.
Also provided are isolated polynucleotide molecules and vectors
incorporating a recombinant RSV genome or antigenome wherein a gene or
gene segment is shifted to a more promoter-proximal or promoter-distal
position within the genome or antigenome compared to a wild type position
of the gene in the RSV gene map. Shifting the position of genes in this
manner provides for a selected increase or decrease in expression of the
gene, depending on the nature and degree of the positional shift.