On Apr. 12, 1985, the Haemophilus influenzae type b (Hib) polysaccharide vaccines (b-CAPSA 1 by Praxis Biologics, Hib-VAX by Connaught, and Hib-IMUNE by Lederle) were licensed. The vaccine was recommended routinely for children at 24 months of age and for children at 15 months of age enrolled in child care facilities. The vaccine was not consistently immunogenic in children <18 months of age.