Abstract: A water-in-oil-in-water (W/O/W) emulsion to be used in an antigen delivery system to induce rapid and long-lasting immunity among populations of livestock, birds, and fish. The external aqueous phase of the W/O/W emulsion contains a thixotropic inorganic salt, such as aluminum hydroxide or alum. The presence of the inorganic salt helps to elicit both a Th1 and a Th2 response from the subject's immune system, and the thixotropic properties of the salt stabilize the water-in-oil-in-water emulsion, thereby providing a longer vaccine shelf life. The antigen dose to be delivered to the subject may be contained in entirely in the internal aqueous phase. Alternatively, a first portion of the total antigen dose may be included in the internal aqueous phase and a second portion is included in the external aqueous phase. The incorporation of a portion of the antigen in the external aqueous phase triggers a more uniform immune response across a vaccinated population.