Patent ID: 8709780

Claim:
A method for producing a purified influenza virus hemagglutinin (HA) antigen, said method comprising the steps of: treating a sample containing the influenza virus HA antigen with a surfactant; bringing said sample after the treatment into contact with hydroxyapatite in the presence of said surfactant under conditions where most of the HA antigen is not adsorbed by hydroxyapatite; and recovering a fraction not adsorbed by the hydroxyapatite, wherein said surfactant comprises at least one of an amphoteric surfactant 3-(3-cholamidepropyl)dimethylammonio-1-propanesulphonate, an nonionic surfactant polyoxyethyeneglycol p-t-octylphenyl ether and an anioni surfactant deoxycholic acid or a salt thereof.