A study found that reports of a neurologic disease called Guillain-Barré syndrome ( GBS ) have been low after 2009 H1N1 vaccination.

Guillain-Barré syndrome is a rare disorder in which the body’s immune system attacks part of the peripheral nervous system, causing tingling and weakness of the arms and legs. While it is not fully known what causes GBS, it is known that about two-thirds of people who get Guillain-Barré syndrome do so several days or weeks after they have been sick with diarrhea or a respiratory illness.
Except for the swine flu vaccine used in 1976, no other influenza vaccines have been clearly linked to GBS. It was not anticipated that the 2009 H1N1 vaccine would be associated with an increased risk of Guillain-Barré syndrome.

Researchers analyzed information obtained from the Centers for Disease Control and Prevention ( CDC ) and Food and Drug Administration ( FDA ) Vaccine Adverse Event Reporting System ( VAERS ) and found that there were 35 reports of GBS following 2009 H1N1 vaccination around the country by the end of the year 2009. This amounts to 3.5 reports of Guillain-Barré syndrome per 10 million people vaccinated.
All cases of GBS except one were reported within six weeks of vaccination, with 23 cases reported within the first two weeks after vaccine administration. One report of death and one of disability were reported in the 33 patients who were hospitalized.

The number of GBS cases reported by the same researcher was only slightly higher after seasonal flu vaccination in 2009: 57 reports of Guillain-Barré syndrome were received by VAERS , an estimated rate of 7.3 reports of Guillain-Barré syndrome per 10 million vaccinations. The rate of GBS in the general population is estimated to be between one to four cases per 100,000 persons per year.

Since VAERS receives voluntary reports of adverse events from manufacturers, providers, vaccines, and caregivers, cases of illness may be either over or underreported, and calculation of actual rates is not possible. VAERS cannot determine cause-and-effect, and an adverse event report only indicates that the event occurred sometime after vaccination.

Source: American Academy of Neurology, 2010

XagenaMedicine2010


Link: Xapedia - Medical Encyclopedia