According to Reuters, a soon to be published British study will confirm a link between Pandemrix, a swine flu vaccine produced by GlaxoSmithKline (GSK), and the development of narcolepsy. Approximately, 800 children of the some 30 million Europeans that received the vaccine during the 2009-2010 season when it was distributed, have developed narcolepsy. This incidence of narcolepsy represents a seven-to-thirteen-fold increase in frequency over the general population, which strongly suggests the occurrence of the disorder is linked to the vaccinations.
The connection between the vaccine and narcolepsy was first identified in Finland and Sweden in 2010 and then subsequently seen in Norway, Ireland, and France. French researchers also noted some evidence of an increase in narcolepsy in adults. Now, it appears, authorities will release findings that also confirm the connection in Britain.
In response to the initial findings, the European Medicines Agency issued a recommendation that the vaccine not be given to individuals under 20 years old, and the vaccine is not currently used at all in Europe.
It is not the active viral component of the vaccine that seems to produce the side effect, but rather an adjuvant additive included in the formulation to make the vaccine more potent. It is thought that the adjuvant AS03 in the GSK swine flu vaccine--added to trigger a stronger immune response to the vaccine--may also simulate some sort of autoimmune response in a small number of susceptible individuals resulting in the narcolepsy disorder.
Pandemrix was never licensed for use in the United States, nor have been any other flu vaccines containing an adjuvant. Only aluminum salts, which have been used as vaccine adjuvants for more than 70 years, are approved for use Federal Drug Administration (FDA), and they are only included in a few vaccines, such as hepatitis A, hepatitis B, and diphtheria-tetanus-pertussis.
Just this past November, however, the FDA Product Advisory Committee unanimously recommended approval of another GSK vaccine containing the AS03 adjuvant in spite of its possible connection with narcolepsy. While this recommendation in light of the current investigations is surprising, it is important to note that the data linking the adjuvant to narcolepsy is still preliminary. Just last October, the European Medicines Agency noted the evidence was insufficient to draw firm conclusions about the cause for the narcolepsy. Perhaps the soon-to-be published British study will provide more definitive data.