AS03

AS03 (for "Adjuvant System 03") is the trade name for a squalene-based immunologic adjuvant used in various vaccine products by GlaxoSmithKline (GSK). It is used, for example, in GSK's A/H1N1 pandemic flu vaccine Pandemrix. Also in Arepannix and the new Q-pan for H5Ni influenza.

A dose of AS03 adjuvant contains

• 10.69 mg squalene
• 11.86 mg DL-α-tocopherol
• 4.86 mg polysorbate 80

Concerns/controversy

AS03 is cited as the "likely cause" of dozens of acute narcolepsy cases in Finland.

There was increased risk of anaphylaxis following administration of 2009 AS03-adjuvanted monovalent pandemic A/H1N1 vaccine. Anaphylaxis after trivalent influenza vaccination is typically reported at a rate of <1 per million doses. In Quebec, Canada, anaphylaxis following administration of the monovalent AS03-adjuvanted H1N1pdm09 vaccine was reported through passive surveillance at a rate of 8 per million doses administered. This was 20 times higher than the reporting rate for non-adjuvanted trivalent vaccines administered during the six previous seasons. However, adequate estimation of the incidence of anaphylaxis is hindered by wide variations in definitions and diagnosis. Summary of paper:

• Quebec passive surveillance showed an increase in anaphylaxis after H1N1pdm09 vaccination.
• Many cases which were reported as other AEFI also met the criteria for anaphylaxis.
• Anaphylaxis was likely underrecognized and its incidence higher than passively observed.
• Incidence of anaphylaxis is estimated at 13 per million doses administered.
• Enhanced public awareness is unlikely to be the predominant explanation for this increase.

See also

• 2009 flu pandemic
• MF59 – another squalene-based adjuvant by Novartis
• AS04 – another adjuvant by GSK