Multiple triggers including vaccination have been implicated in the development of the Guillain-Barré Syndrome (GBS), a monophasic illness in which inflammation of peripheral nerves can result in paralysis, loss of deep tendon reflexes, facial weakness and difficulty swallowing. Several different vaccine are reported as antecedent triggering events to GBS including the Swine influenza (A/new Jersey) vaccine in 1976-77, oral polio vaccine, pnuemococcal vaccine and tetanus toxoid. Over the past several decades many epidemiological studies have established that the incidence of GBS is relatively low, l-2/100,000 population year. Clusters of disease can variably occur throughout the year and may be associated with a particular inciting event. One such cluster was reported to follow the A/New jersey influenza vaccination program. Estimates of the relative risk of developing GBS in the immediate six to eight weeks after vaccination were increased 4.0 to 7.6-fold. However, four studies done during 1978-1988 were not able to find a significant increased risk of GBS following influenza vaccination suggesting that the potential factors contributing to the number of cases associated with the A/New Jersey vaccine were unique to that particular vaccine. This issue however was re-examined recently following a doubling in the number of GBS cases reported after receipt of influenza vaccine in 1993-1994 compared to the previous year as monitored by the Centers for Disease Control (CDC) and the Food and Drug Administration.

The University of Maryland School of Medicine in association with the CDC undertook a collaborative investigation to estimate the relative risk associated with the influenza vaccines during 1992-93 and 1993-94, the results of which were published in the December 17, 1998 issue of the New England journal of Medicine. Patients with GBS were identified from hospital discharge data bases of four states including Illinois, Maryland, North Carolina, and Washington four study states comprised a total population (18 years and older) of 21.2 million (92-93) and 21.4 million (93-94). Vaccination histories of patients were obtained by telephone interviews and confirmed with the vaccine providers. Vaccine coverage in the population of each state was determined through a random-digit-dialing survey. Over 1000 charts were reviewed and the diagnosis of GBS confirmed in 273, of which 180 patients were interviewed. Vaccine providers confirmed influenza vaccination in the 6 weeks prior to onset of GBS in 19 patient, 9 of which occurred within 9-12 days of vaccination. All vaccine associated cases occurred in ages 45 and higher. The relative risk for GBS associated with vaccination for both years was 1.7., suggesting that only slightly more than one additional case in one million vaccinated patients. Regardless, given that influenza causes more than 20,000 deaths per year in the United States, the risk of developing GBS following a vaccine is very small and should not preventing those people at risk from influenza from obtaining the vaccine. Groups at particular risk include the elderly patients with chronic disease, and people who regularly interact with large groups of people such as teachers and health care professionals.

It is not possible to make vaccination recommendations for patients who are recovering from GBS or have had GBS following vaccination, since there are no reliable data on either of these issues. The decision to take the vaccine under these two circumstances must represent a personal decisions made between a patient and their physician. Additional information and answers to questions can be obtained from the CDC web site at: www.cdc.gov/nip/vacsafe.