Infant protection from invasive Haemophilus influenzae type b disease using the PRP-OMPC conjugate vaccine: An update

Invasive disease caused by Haemophilus influenzae type b (Hib) is a major health concern, particularly in children under 5 years of age and vulnerable populations. Use of Hib conjugate vaccines has significantly reduced the incidence of Hib disease. Among these, the polyribosylribitol phosphate-outer membrane protein complex (PRP-OMPC) conjugate has demonstrated uniquely robust immunogenicity in infants compared to PRP conjugated to tetanus toxoid. Vaxelis, using the PRP-OMPC conjugate, was well tolerated and immunogenic as shown through the clinical development program. Additional studies that are recently published address previously open questions regarding Vaxelis, including immunogenicity after the first infant dose, co-administration with meningococcal B vaccine, and interchangeability with other hexavalent vaccines. This brief review summarizes recently published Vaxelis data, with potential implications for ongoing control of invasive Hib disease in Europe.