Tolerance of initial diphtheria-tetanus-pertussis immunization in preterm infants.

With the use of neurologic examinations, cranial sonograms, electroencephalograms, an cry analyses, we assessed neurologic function before and after an initial diphtheria-tetanus-pertussis immunization in 22 very low birth weight infants. Mean birth weight was 1036 +/- 137 gm; mean gestational age was 28.0 +/- 1.3 weeks. All 22 infants had recovered from respiratory distress syndrome, 10 infants had been treated for invasive bacterial or fungal infection, and 9 infants had had previous intraventricular hemorrhages. Initial immunization was administered at a mean age of 71 +/- 15 days (range 57 to 120 days) and a mean weight of 1895 +/- 245 gm (1370 to 2280 gm). Clinical reactions were mild and transient. No postimmunization changes in neurologic examinations or objective studies were noted compared with results of preimmunization studies. These findings support the safety of administering an initial diphtheria-tetanus-pertussis immunization to very low birth weight infants at the recommended age of 8 weeks.