Monitoring System for Adverse Events Following Immunization: Risk Factors for Convulsions After Vaccination
Surveillance for adverse effects of immunization began at the Centers for Disease Control in 1976–1977 with the A New Jersey, Swine Flu Vaccination campaign. This surveillance effort successfully detected an increased incidence of Guillain-Barré syndrome (GBS), subsequently estimated at slightly less than one excess case of GBS attributable to the influenza vaccine for every 100,000 vaccines, and stimulated the development of an ongoing system to collect reports of illness following immunization. When compared to responders with non-neurologic events, the persons had an increased risk of 8.9- and 8.6-fold, respectively. There were insufficient data to make any assessment of the risk of more severe neurologic events, such as encephalitis or encephalopathy. Persons reporting a neurologic adverse event following a measles-containing vaccine were 5.2 times more likely to have a personal history of convulsions than those with a non-neurologic event. Persons reporting febrile convulsions were 5.6 times as likely to have a prior history of convulsions.