599881 Disclosed is a squalene-containing oil-in-water emulsion vaccine adjuvant which is obtained by a method comprising: (i) formation of a squalene-containing oil-in-water emulsion having a first average oil droplet size (which is preferably 5000 nm or less)； (ii) microfluidization of the squalene-containing oil-in-water emulsion to form a second emulsion having a second average oil droplet size which is less than the first average oil droplet size (preferably 500 nm or less)； and (iii) filtration of the second emulsion using a hydrophilic double-layer polyethersulfone membrane with a first layer having a pore size >；0.3&mu；m, and a second layer having a pore size <；0.3&mu；m, thereby providing a vaccine adjuvant. Also disclosed is a vaccine kit comprising an emulsion adjuvant as defined above and an antigen component.
