On Apr. 13, 1990, the Immunization Practices Advisory Committee (ACIP) recommendations for use of any of the three licensed Hib conjugate vaccines (ProHIBIT, HibTITER, and PedvaxHIB) for children as young as 15 months of age were published in MMWR. Unvaccinated children 15-59 months of age may be given any one of the three conjugate vaccines licensed for this age group.

Haemophilus influenzae type b (Hib) is the leading cause of invasive bacterial disease among children in the United States. Before effective vaccines were introduced, one in 200 children developed invasive Hib disease by the age of 5 years.