The invention provides an improved BRSV vaccine composition, which advantageously provides immunity from infection after a single administration. The composition comprises a modified live BRS virus and an adjuvant, which in combination provide immunity from BRSV infection after a single administration, and elicit an immune response specific to BRSV and including cell-mediated immunity and local (secretory IgA) immunity. In a preferred embodiment, the BRS virus is strain 375, and the adjuvant comprises an unsaturated turpin hydrocarbon, preferably squalene or squalane, and a polyoxypropylene-polyoxyethylene block copolymer, most preferably one where the copolymer has a polyoxypropylene (POP) component with an average molecular weight of about 3250 to 4000 and the polyoxyethylene (POE) component comprises about 10-20% of the total molecule. The adjuvant may optionally include a surfactant, preferably a polyoxyethylenesorbitan monooleate.
