Anyone can file a report with the VAERS data base, making the accuracy of the reports unreliable, said Dr. James Sejvar, a CDC neuroepidemiologist. The data base is mainly meant to serve as an early warning system for vaccine-related issues.
Without examining medical records to substantiate that the reported illnesses were actually Guillain-Barre syndrome, he said it's wrong to suggest any association between the syndrome and the vaccine, let alone say that the vaccine caused the illness.
"You cannot use those data to infer anything about a link between a vaccine and a particular event," Sejvar said. "VAERS is one of several mechanisms by which we are assessing the safety of the vaccine, and all data suggest the risk of any adverse event from the vaccine is greatly overweighed by the benefits of vaccination."
The study was to be presented April 13 at the American Academy of Neurology's annual meeting in Toronto.
In Guillain-Barre syndrome, the immune system attacks a portion of the peripheral nervous system. The syndrome can range from mild to severe, causing tingling and weakness of the legs, and spreading to the arms and upper body. While most people recover fully, some have long-term weakness. In severe cases, Guillain-Barre syndrome can cause death.
The cause of the syndrome isn't fully understood, but the onset of symptoms is usually preceded by an infection, Souayah said. About two-thirds of people with the syndrome report having a respiratory or gastrointestinal illness several days or weeks before developing Guillain-Barre syndrome.
Guillain-Barre syndrome and flu vaccine fears first emerged in 1976, when 43 million people were vaccinated against the swine flu. About 500 people developed Guillain-Barre syndrome, and 25 died.
No other influenza vaccines have been clearly linked to Guillain-Barre syndrome, Souayah said. He and his colleagues also found about 57 cases of Guillain-B
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