Guillain-Barre rate low post-H1N1 vaccine

TORONTO, April 14 (UPI) -- Incidence of Guillain-Barre syndrome, linked to the swine flu vaccine used in 1976, has been low after last year's H1N1 vaccination, Canadian researchers said.

An analysis of data from the Centers for Disease Control and Prevention and U.S. Food and Drug Administration Vaccine Adverse Event Reporting System found there were 35 reports of Guillain-Barre syndrome nationwide by the end of last year -- or 3.5 per 10 million people vaccinated with H1N1.

Guillain-Barre syndrome incidence was slightly higher for last year's seasonal flu vaccine -- 57 reports of were received by Vaccine Adverse Event Reporting System, or an estimated rate of 7.3 cases per 10 million vaccinations.

Study author Dr. Nizar Souayah of the New Jersey Medical School in Newark said Guillain-Barre syndrome is a rare disorder in which the body's immune system attacks the nervous system, creating weakness of the arms and legs.

It is unclear what causes the disorder, but two-thirds who had it contracted it after being sick with diarrhea or respiratory illness. The rate of Guillain-Barre in the general population is estimated to be between 1-4 cases per 100,000 persons per year, Souayah said.

Except for the swine flu vaccine in 1976, no other influenza vaccine has been clearly associated with Guillain-Barre syndrome, Souayah said.

The findings were presented at the American Academy of Neurology's 62nd annual meeting in Toronto.