Risk of Guillain-Barré syndrome after measles-mumps-rubella vaccination.

OBJECTIVE To assess the postulated causal association between measles-mumps-rubella (MMR) vaccination and Guillain-Barré syndrome (GBS). STUDY DESIGN Active retrospective study based on linkage of the nationwide hospital discharge register with individual vaccination records. All patients hospitalized for treatment of GBS in Finland between November 1982 and December 1986 were included in the study. RESULTS During the study period, 189 patients were hospitalized for treatment of GBS, and approximately 630,000 vaccine recipients received 900,000 doses of MMR vaccine; 24 of the 189 patients represented the prevailing target population for MMR vaccination, of whom 20 were vaccinated. MMR vaccination did not cause any increase over the background incidence of GBS, and no clustering of cases of GBS occurred at any time point after administration of MMR vaccine. The interval between vaccination and onset of symptoms of GBS exceeded the designated risk period of 6 weeks in all cases, varying from 80 days to years. MMR vaccination after recovery from GBS did not cause relapses of the illness. Respiratory or gastrointestinal tract infection predated the onset of GBS by 3 to 30 days in 20 (83%) of the 24 patients. CONCLUSIONS No causal association seems to prevail between MMR vaccination and GBS.