Abstract
H. influenzae type b (HIB) disease was observed during a 14 mo. period in 7 of 48 infants attending a day-care center. Surveillance studies showed that 28 (58%) infants had positive nasopharyngeal cultures for HIB; 4 infants were colonized with HIB for 9-12 mo. Ampicillin trihydrate prophylaxis failed to reduce the HIB carrier rate. HIB polysaccharide vaccine was administered to 34 of the children. Sera obtained prior to immunization showed detectable antibody in all infants. Only 9 (26%) infants had 2-fold or greater rises in serum HIB antibody titers after vaccination. Antibody response was independent of age, preimmunization antibody concentration and HIB carrier status. In 1 infant, HIB meningitis developed 4 mo. after she received polysaccharide vaccine. HIB is highly contagious in closed populations of young, susceptible infants.

This publication has 3 references indexed in Scilit: