From the BBC: Link between narcolepsy and flu vaccine investigated
Health officials are investigating a link between narcolepsy and the Pandemrix vaccine in two people who were treated for swine flu.
Northern Ireland's Chief Medical Officer has confirmed to the BBC, that Northern Ireland had become the latest country to report suspected cases of the sleeping disorder.
Dr Michael McBride said the vaccine was used during the flu pandemic of 2009.
"Let's be clear - this is not the vaccine that we use today," he added...Let's be clearer in this blog. The trivalent vaccine used today does include the swine flu (H1N1) hemagglutinin antigen --the main immunizing ingredient in swine flu vaccines. According to the FDA, the 2011-2012 vaccine's "A/California/7/09 (H1N1)-like virus is the pandemic (H1N1) 2009 influenza virus." In the UK and many countries, but not the US, the swine flu vaccine used in 2009-10 also contained a novel adjuvant; in the UK this was ASO3. It is of interest that in one important study, most, but not all cases of post-vaccination narcolepsy were associated with the ASO3-adjuvanted vaccine, while other cases were associated with the plain vaccine...which contained the same ingredients as are found in the current flu vaccine. So far, neither ASO3 adjuvant nor hemagglutinin antigen has been implicated as "the" cause of the narcolepsy outbreak. Certainly, the European Medicines Agency has no clue, below:
In the past six months, the number of narcolepsy cases in Beijing in China, and Scandinavian countries including Finland has risen significantly...
With concern growing about the potential side effects of Pandemrix, the vaccine used during the pandemic flu in 2009, the European Medicines Agency completed a review of the drug in July 2011.
It concluded that the benefits of Pandemrix continued to outweigh its risks, but that it may only be used in people under 20 if the recommended annual seasonal vaccine was not available and if immunization against H1N1 was still needed. [Would the person who calculated this crazy risk - benefit analysis please stand up?---Nass]
Swine influenza viruses though commonly belong to the H1N1 subtype, other subtypes like H1N2, H3N1, H3N2 are also known to be circulating in pigs. Pigs, on the other hand, are more susceptible to being infected with avian influenza viruses, human seasonal influenza viruses and swine influenza viruses, allowing the genes from the viruses to mix and result in an influenza virus containing genes from a number of sources; this is called a reassortant virus. Although swine influenza viruses are species specific, they can in extreme conditions make a crossover to cause disease in humans.
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