AS03 (for "Adjuvant System 03") is the trade name for a squalene-based

immunologic adjuvant In immunology, an adjuvant is a substance that increases or modulates the immune response to a vaccine. The word "adjuvant" comes from the Latin word ''adiuvare'', meaning to help or aid. "An immunologic adjuvant is defined as any substance tha ...

used in various vaccine products by

GlaxoSmithKline GSK plc, formerly GlaxoSmithKline plc, is a British multinational pharmaceutical and biotechnology company with global headquarters in London, England. Established in 2000 by a merger of Glaxo Wellcome and SmithKline Beecham. GSK is the tent ...

(GSK). It is used, for example, in GSK's

A/H1N1 In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus. Major outbreaks of H1N1 strains in humans include the Spanish flu, the 1977 Russian flu pandemic and the 2009 swine flu pandemic. It is an orthomyxovirus ...

pandemic flu vaccine

Pandemrix Pandemrix is an influenza vaccine for influenza pandemics, such as the 2009 flu pandemic. The vaccine was developed by GlaxoSmithKline (GSK) and patented in September 2006. The vaccine was one of the H1N1 vaccines approved for use by the Europe ...

. It is also in Arepanrix and the Q-pan for H5N1 influenza. A dose of AS03 adjuvant containsPandemrix – Summary of product characteristics
,

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Eur ...

websi
European Medicines Agency website
* 10.69 mg squalene * 11.86 mg DL-

α-tocopherol α-Tocopherol is a type of vitamin E. It has E number "E307". Vitamin E exists in eight different forms, four tocopherols and four tocotrienols. All feature a chromane ring, with a hydroxyl group that can donate a hydrogen atom to reduce free r ...

* 4.86 mg polysorbate 80 In the 2009 influenza pandemic, vaccines containing AS03 delivered a stronger immunogene response against pandemic H1N1 influenza than non-adjuvanted vaccines, despite their containing lower levels of viral

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respon ...

. Small observational studies reported from Finland and Sweden in 2012, and larger studies from Ireland reported in 2012, and reported in each of England, Norway and France in 2013, found an association between

narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affect ...

and an A(H1N1)pdm09 vaccine that used AS03 adjuvant; the rates ranged from one in 16,000 doses to one in 50,000 doses. As of 2016 it was unclear whether or not the adjuvant was responsible; other suspected causes include genetic susceptibility, exposure to A(H1N1)pdm09, manufacturing impurities, and combinations of these factors.

References

See also