An Epidemiologic and Clinical Evaluation of Guillain-Barré Syndrome Reported in Association With the Administration of Swine Influenza Vaccines

Abstract

As a result of a court order, computerized summaries of approximately 1,300 cases reported as Guillain-Barré syndrome by state health departments to the Centers for Disease Control during the intensive national surveillance instituted following the swine influenza vaccination program in 1976-1977 became available for further study. Although the data were not uniformly adequate to confirm the diagnosis of Guillain-Barré syndrome, they were sufficient to enable classification according to extent of motor involvement. Vaccinated cases with "extensive" paresis or paralysis occurred in a characteristic epidemiologic pattern closely approximated by a lognormal curve, suggesting a causal relationship between the disease and the vaccine. Cases with "limited" motor involvement showed no such pattern, suggesting that this group included a substantial proportion of cases which were unrelated to the vaccine. The effect attributed to the vaccine lasted for at least six weeks and possibly for eight weeks but not longer. The relative risk of acquiring "extensive" disease over a six-week period following vaccination ranged from 3.96 to 7.75 depending on the particular baseline estimate of expected normal or endemic incidence that was chosen. Correspondingly, the number of cases that could be attributed to the vaccine over the six-week period ranged from 211 to 246, or very slightly higher over an eight-week period if the lowest baseline estimate was used. The total rate of Guillain-Barré syndrome cases attributed to prior use of the vaccine was 4.9 to 5.9 per million vaccinees.

Epidemiologic features of Guillain-Barré syndrome in São Paulo, Brazil

“…Many other identified pathogens have been reported, including human immunodeficiency virus, as being triggers for GBS, but these have been reported in small series and anecdotal reports, for which there is a lack of statistically valid evidence 27 . The association with vaccinations has been reported in many studies as antecedent events 14 , but the only case with a satisfactorily explained mechanism is that of the rabies vaccines. Two separated case control studies failed to show a significant association between the occurrence of GBS and immunization, although they have found an increased risk likely to be four to five-fold 28 .…”

“…We still have difficulties with its definition and there is not a standard diagnostic test of reference. Epidemiological studies of GBS are rare, with only ten series that include more than one hundred patients to date [10][11][12][13][14][15][16] . This occurs partially because the clinical, laboratory and electrodiagnostic criteria, although well defined, are difficult to apply retrospectively.…”

Guillain–Barré syndrome: a century of progress

“…The report was questioned on several methodological issues, and an independent review of GBS cases included noted that many did not meet the accepted diagnostic criteria -the original study consequently received fierce criticism 19 . The US Justice Department eventually convened an independent assessment of the data by an expert panel, who confirmed that, despite methodological flaws of the study, the risk of GBS was elevated and peaked 2-3 weeks after vaccination, with an attributable risk of 0.49-0.59 extra cases per 100,000 adult vaccinees 20 . Several subsequent influenza immunization programmes have been monitored for an increased incidence of GBS; in 1998, a retrospective case series of patients with GBS confirmed an increased risk of GBS (RR 1.7, 95% CI 1.0-2.8)in the 6 weeks after influenza vaccination 21 .…”

Suspect Guillain-Barré syndrome in a male rhesus macaque (Macaca mulatta)

“…In animals, GBS-like diseases have been reported following a rabies (Hemachudha et al, 1988) or swine influenza vaccination (Langmuir et al, 1984).…”