The risk of Guillain-Barré syndrome after tetanus-toxoid-containing vaccines in adults and children in the United States.

OBJECTIVES This study examined whether there is a risk that tetanus-toxoid-containing vaccines could cause Guillain-Barré syndrome and, if so, how large the risk is. METHODS This study was based on previous active surveillance epidemiological studies of Guillain-Barré syndrome and vaccination history. RESULTS A background rate of 0.3 cases of Guillain-Barré syndrome per million person-weeks has been estimated. By chance, 2.2 people with the syndrome would have received tetanus-toxoid-containing vaccine within the 6 weeks before onset, yet only 1 person had done so. Data on children show similar results. CONCLUSIONS If an association exists, it must be extremely rare and not of public health significance.