A study published on Wednesday in the British Medical Journal (BMJ) has concluded that there is a "causal association" between the swine flu shot and an increased risk of developing narcolepsy. The risk was assessed specifically for children between the ages of 4 and 18.
The study, conducted by scientists working in the U.K., is the latest in a series of similar research projects that have sought to discover whether there is a link between the shot and the development of narcolepsy. Medical records for children diagnosed with the condition between 2008 and 2011 were analyzed by the team to determine their findings.
Here is some of the key information to have emerged from this latest study into the link between the swine flu shot and narcolepsy in children.
* Researchers looked at the medical records of some 245 children in the U.K., 75 of whom had gone on to be diagnosed with narcolepsy after January of 2008. Of those 75 children, 11 had been vaccinated with the swine flu shot, known formally as the ASO3 adjuvanted pandemic A/H1N1 2009 influenza vaccine, before onset.
* As Reuters noted in a report regarding the study on Wednesday, similar research conducted in Finland, Ireland, and Sweden reached the same conclusion regarding the link between the swine flu shot and narcolepsy.
* The BMJ study concluded that the swine flu shot increased the risk that a child would develop narcolepsy by more than 14-fold. Put another way, researchers estimated that the odds were that between 1 in 57,500 and 1 in 52,000 children given the swine flu shot would go on to develop narcolepsy.
* Researchers for the BMJ study did make mention of the possibility that results could have been skewed slightly by "more rapid referral of vaccinated children," after results from previous studies into the swine flu shot's influence on the development of narcolepsy had begun to be released.
* A spokesman for GlaxoSmithKline, which manufactures the Pandemrix vaccine that has been at the center of all of these research studies, told Reuters that the company wants to "understand more about the potential role" of the drug "in the development of narcolepsy."
* The spokesman went on to say that "the available data are insufficient" for researchers to conclusively link Pandemrix to an increased risk of narcolepsy in children.
* Bloomberg noted on Wednesday that the European Medicines Agency began recommending the "restricted use" of Pandemrix in anyone under the age of 20, beginning in July of 2011.
* Narcolepsy is believed to be an autoimmune disorder that interferes with the brain's sleep centers, causing irregular sleep-wake cycles.
Vanessa Evans is a musician and freelance writer based in Michigan, with a lifelong interest in health and nutrition issues.
- Public Health