Abstract: The present invention provides a W/O/W type oil adjuvant vaccine containing an outer aqueous phase containing 0.5 wt %-20 wt % of a polyethylene glycol derivative having a molecular weight of 400-20,000, and an inner aqueous phase containing a biologically acceptable and effective amount of an antigen. The constitution of the present invention that a polyethylene glycol derivative having a specific molecular weight is contained in the outer aqueous phase enables preparation of a W/O/W type oil adjuvant vaccine showing a high adjuvant effect, reduced side effects such as topical response, superior preparation stability and superior workability to allow a person to give an injection easily due to the lowered viscosity.

Abstract: An improved method for purification of HBs antigen comprising passing a partially purified HBs antigen prepared from blood plasma or serum through a column filled with an anion exchanger which may be equilibrated with a buffer solution having a specific ionic strength and pH level, and further passing the resulting effluent through a column filled with a cation exchanger which may be equilibrated with a buffer solution having a specific ionic strength and pH level. The HBs antigen obtained by the present invention is highly purified and is useful for preparing vaccine for preventing Viral Hepatitis Type B.