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Notice to Readers Unlicensed Use of Combination of Haemophilus influenzae type b Conjugate Vaccine and Diphtheria and Tetanus Toxoid and Acellular Pertussis Vaccine for Infants

The only licensed combination vaccine containing Haemophilus influenzae type b (Hib) conjugate vaccine and diphtheria and tetanus toxoid and acellular pertussis vaccine (DTaP) is for use in children aged 15-18 months. The Food and Drug Administration and CDC's National Immunization Program have received reports from state health departments that in certain clinical settings, licensed Hib conjugate vaccines and DTaP vaccines are being combined for administration as a single injection in infants aged 2, 4, and 6 months. These vaccines (DTaP/Hib) have not been licensed for combination use in the primary vaccination series in infants. Clinical studies in infants conducted under Investigational New Drug applications have demonstrated that using some combination vaccine products containing Hib vaccine may induce a suboptimal immune response to the Hib vaccine component. Additional information about further vaccination actions that may be required for the infant who received an unlicensed DTaP/Hib combination product is available from CDC's Immunization Hotline, telephone (800) 232-2522.

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