To the Editor:—The possibility that severe neurologic reactions may occur after the administration of pertussis vaccine has been widely recognized since the report of Byers and Moll in 1948.1 In the hope that better standardization of vaccines might decrease the incidence of such reactions, new tests for the toxicity and potency of pertussis vaccines were adopted in 1948 and 1953, respectively.2,3 Reports of reactions have appeared since 1953, but it is not clear if the vaccines used had passed the present requirements. To determine if neurologic reactions have occurred after the administration of vaccines meeting the standards now in effect, a questionnaire was sent to 104 heads of departments of pediatrics in medical schools and to directors of children's hospitals in the United States. Replies were received from 75.
Twenty-two children with some type of encephalopathy following pertussis vaccine administration were observed in 13 institutions from 1955
CHRISTENSEN CN. MORE RISKY TO GIVE, OR NOT TO GIVE?. Am J Dis Child. 1963;105(4):417. doi:10.1001/archpedi.1963.02080040419015