Haemophilus influenzae type b disease. Incidence in a day-care center
C. M. Ginsburg, G. H. McCracken Jr, S. Rae and J. C. Parke Jr
Haemophilus influenzae type b (HIB) disease was observed during a 14-month
period in seven of 48 infants attending a day-care center. Surveillance
studies showed that 28 (58%) infants had positive nasopharyngeal cultures
for HIB; four infants were colonized with HIB for nine to 12 months.
Ampicillin trihydrate prophylaxis failed to reduce the HIB carrier rate.
Haemophilus influenzae type b polysaccharide vaccine was administered to 34
of the children. Sera obtained prior to immunization showed detectable
antibody in all infants. Only nine (26%) infants had twofold or greater
rises in serum HIB antibody titers after vaccination. Antibody response was
independent of age, preimmunization antibody concentration, and HIB carrier
status. In one infant, HIB meningitis developed four months after she
received polysaccharide vaccine. This outbreak emphasizes that HIB is
highly contagious in closed populations of young, susceptible infants.
