Critical evaluation of the role of immunization as an etiological factor of infantile spasms

Abstract

One hundred and ten cases of infantile spasms with detailed information about immunization available were selected as the masterial to evaluate the significance of immunization as an etiological factor of infantile spasms. In 80% of the cases, immunization could not be considered to have any relation with causation of infantile spasms, because 44 cases (40%) never had innoculations as yet, and other 44 cases (40%) had been immunized by some vaccines over one month before or after the onset of the disease. The remaining 22 cases, in whom immunization had been performed within one month before the onset of the disease, constituted the candidates for further study. The age of onset of the disease of the candidate group ranged from 3 to 9 months of age with peak incidence at 4 to 5 months old, exactly identical with that of patients with infantile spasms in general. The kind of vaccines concerned included DPT triple vaccines in 15 cases, smallpox vaccine in 4, antipolio live vaccine in 1, anti-Japanese encephalitis vaccine in 2. Causal relationship of immunization with infantile spasms in each patient was evaluated on the basis of the following three apsects: 1. Any other causal factors except immunization should be absent. 2. Psychomotor development before onset of the disease should be normal. 3. Interval from immunization to onset of the disease should be lied: a) Within 48 hours, in the case of pertussis vaccine, b) within 18 days, in the case of smallpox vaccine or anti-Japanese encephalitis vaccine or antipolio vaccine. Only five cases (4.8% of the total) were able to classify into the compatible group which should fulfill all the above three criteria. The small figure may easily be explicable on the assumption that the natural onset of spasm is chronologically superposed by chance over immunizations which have to be done within the first year of life.