Swine flu vaccine used in Europe in the year 2009 was linked to sleep disorder narcolepsy in rare cases. Now a new research offers clue as to what happened.
Pandemrix vaccine, manufactured by GlaxoSmithKline PLC (GSK) was recommended by the UK government during the swine flu outbreak in 2009, but was withdrawn after medical records showed a growing number of narcolepsy cases among those who received the vaccine.
Researchers believe that the vaccine could harm a critical portion of the brain used for regulating sleep. The vaccine caused chronic illness in about one in 55,000 recipients.
The H1N1 strain contains a protein that is similar to a brain receptor that regulates wakefulness by producing the hormone hypocretin, the antibodies triggered by the vaccine could have destroyed the neurons as well said the researchers.
"There's a lot of evidence now to suggest that narcolepsy is an autoimmune disease. In our study, we found antibodies that could cross-react to both the flu protein produced by the vaccine and receptors on the neurons," Sohail Ahmed, global head of clinical sciences at Novartis Vaccines, and the lead author of the study, said, according to the Guardian.
"We are actively conducting research into the observed association between Pandemrix and narcolepsy and the interaction this vaccine might have had with other risk factors in those affected," said, a GSK spokeswoman.
Narcolepsy is an incurable, chronic brain disorder marked by excessive daytime sleepiness and possible severe nightmares.
The study is published in the journal Science Transitional Medicine.