DTP VACCINATION RESULTS IN "NO SIGNIFICANT INCREASE" IN SEIZURES

DTP VACCINATION RESULTS IN "NO SIGNIFICANT INCREASE" IN SEIZURES among children, according to an article by Marie Griffin, MD, Vanderbilt University, et al., in the March 22 issue of The Journal of the American Medical Association. The researchers conclude that "no child" in their study population "had the onset of encephalopathy, epilepsy, or other serious neurological disease in the first week following DTP [diptheria-tetanus-pertussis] immunization. Indeed, there was no significant increase in febrile, afebrile, or acute symptomatic seizures in the early postimmunization period, compared to the control period of 30 or more days following DTP immunization." Griffen, et al., evaluated 38,171 predominantly poor, non-white Tennessee children receiving innoculations under the state's Medicaid program. All children received at least one DTP immunization at a median age of two months, while 95% had a second at a median age of five months, 87% a third at a median age of eight months, and 67% a fourth at a median age of 23 months, representing a total of 107,154 immunizations. Follow-up began after the first immunization and was continued until the child's third birthday, or during "the time when most DTP immunizations are administered and the time of highest incidence of childhood seizures." Possible seizures were discovered by screening Medicaid inpatient and outpatient claims under a variety of diagnostic codes. Using this method, the researchers found "potential outcomes of interest" in 1,187 children, and were able to secure medical records for 828, or 70%, of these cases. Upon examination, these records revealed 358 which met the researchers' case definition, consisting of 213 simple and 64 complex febrile seizures, 42 afebrile seizures, 37 acute symptomatic seizures and two encephalopathies. Among these case, Griffin, et al., found six febrile seizures in the three days following DTP immunization, or a relative risk of 1.5 times that of the control period, established as the 30 days following immunization. After accounting for children with a history of seizures before immunization, this risk was reduced to 1.3. Similar analysis found one case of afebrile seizure and a risk factor of 1.3. According to the researchers, no symptomatic seizures were discovered during the three days following immunization. The researchers acknowledge that their finding of no significant increase in the risk of febrile seizures following DTP immunization "has not been consistently seen in other studies" which have calculated risk factors from 3.7 to 5.6 immediately following immunization. The researchers attributed this to the possibility of "the low precision of the estimates of the risk of febrile seizures in the immediate postimmunization period" in their study, and possible problems in the completeness of reporting less serious neurological events. The researchers maintain, however, that their results show a "greater concordance" with other studies as to whether the risk of serious neurological disorders increases following DTP immunization, thus "reinforcing the findings of previous investigators working in other populations that serious neurological events are rarely, if ever, caused by DTP immunization. The study's results contradict the widely-held assumption that a small number of cases of seizures and encephalopathy are an unavoidable result of immunizing children with the DTP vaccine. For instance, the American Academy of Pediatricians currently calculates the incidence of encephalopathy resulting from DTP immunization at one in 140,000, with permanent neurological deficits resulting in one in every 330,000. Injuries believed to be associated with the DTP vaccine were the impetus behind passage of the National Childhood Vaccine Injury Compensation Act of 1987, under which victims are compensated from a trust funded by a surcharge on the price of each vaccine.