CARRIAGE OF HAEMOPHILUS-INFLUENZAE TYPE-B IN CHILDREN AFTER WIDESPREAD VACCINATION WITH CONJUGATE HAEMOPHILUS-INFLUENZAE TYPE-B VACCINES

Rates of invasive Haemophilus influenzae type b (Hib) disease in child ren decreased very rapidly after licensure of Hib conjugate vaccines. A role for a vaccine-related reduction in nasopharyngeal carriage of H ib has been suggested. We studied oropharyngeal carriage of Hib and va ccination rates in a population of 2-to 5-year-old children in metropo litan Atlanta. Among 584 children 75% were vaccinated with an Hib conj ugate vaccine, 17% had not been vaccinated and 8% had no vaccination r ecords available. Forty-one percent of the children were colonized wit h H. influenzae. One child was colonized with Hib. Hib carriage (0.17% ; upper 95% confidence interval boundary, 0.97%) was substantially low er than the estimates of Hib carriage from prior studies of children, who had not received Hib conjugate vaccines. Our data are consistent w ith a decline in Hib carriage induced by widespread use of conjugate H ib vaccines, which may have contributed to the decline of Hib disease in United States children.