title: The avian influenza vaccine Emerflu. Why did it fail?
abstract: Emerflu is an inactivated, split-virion pandemic preparedness vaccine, containing 30 μg of hemagglutinin (HA) and 600 μg of aluminum hydroxide adjuvant. It is administered in two doses, 3 weeks apart. Only moderate immunogenicity was evident from clinical studies with the vaccine in adults, and HA antibody responses were below the criteria established by the EMA and US FDA for licensure. With the exception of Australia, the vaccine remains unlicensed. Further clinical development appears to have been suspended, and newer adjuvants such as MF59 and AS03 have since demonstrated safety and superior immunogenicity with lower HA doses. Emerflu is symbolic of the failure of aluminum salts as an adjuvant for influenza vaccines. Reasons for this failure are unclear, and may reflect problems with the adjuvant-antigen complex or interference in the immune response by heterosubtypic immunity.
authors.affiliation: Communicable Diseases Centre, Institute of Infectious Diseases and Epidemiology, Communicable Diseases Centre, 144 Moulmein Road, Singapore, Singapore.
authors.forename: Barnaby E
authors.initials: BE
authors.lastname: Young
authors.forename: Sapna P
authors.initials: SP
authors.lastname: Sadarangani
authors.forename: Yee Sin
authors.initials: YS
authors.lastname: Leo
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000536:Aluminum Hydroxide / Q000008:administration & dosage*; D000914:Antibodies, Viral / Q000097:blood; D002986:Clinical Trials as Topic; D014943:Global Health; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D009500:Neutralization Tests; D017211:Treatment Failure; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated; D000536:Aluminum Hydroxide
keywords: Emerflu; H5N1; adjuvant; alum; avian; influenza; split; vaccine; virion