Clinical and Immunological Risk Factors Associated withHaemophilus influenzaeType b Conjugate Vaccine Failure in Childhood

Abstract

Haemophilus influenzae type b (Hib) conjugate vaccines have proved extremely efficacious in healthy children. True Hib vaccine failures are rare. Hib conjugate vaccines were introduced for routine immunization in the United Kingdom and the Republic of Ireland in 1992. Coincident with this, active prospective and national surveillance via pediatricians, microbiologists, and public health physicians was commenced to assess the clinical and immunological factors associated with vaccine failure. During the 6 years of the study, 115 children with true vaccine failure were reported. Of the children who were vaccinated before 12 months of age, a clinical risk factor was detected in 20%, an immunological deficiency was detected in 30%, and one or both were detected in 44%. Children who were vaccinated after 12 months of age were more likely to have one or both factors (67%). Thirty percent (33 of 105) of children with true vaccine failure had a low Hib antibody response (concentration, <1.0 microg/mL) after disease, but the majority then responded to a further dose of Hib vaccine. Children who develop Hib disease despite vaccination deserve further clinical and immunological evaluation.

Etiología y evolución de las infecciones osteo-articulares 2009-2015: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay

“…La efectividad de la vacunación contra este agente no es 100%, está asociada a la edad del niño, el número de dosis recibidas y las tasas de cobertura vaccinal en la comunidad y factores del hospedero como inmunodeficiencias primarias o secundarias. En esta serie, uno de los dos casos se podría tratar de una falla vaccinal, siendo ésta entendida como el aislamiento de H. influenzae tipo b en un líquido estéril transcurrida una semana o más de la segunda dosis de vacuna en un paciente menor de un año de edad o después de dos semanas de la última dosis de vacuna en pacientes de un año de edad o más 25 . Se necesitaría un análisis completo de la historia clínica en este caso para poder confirmarlo.…”

An epidemiological study of Haemophilus influenzae at a Brazilian day care center

“…For those vaccinated after age 12 months, a single dose of any vaccine should be administered [38]. The use of a booster dose is a controversial question and, in the United Kingdom and the Republic of Ireland, the booster dose is not administered [39]. Children < 1 year of age are considered adequately immunized against Hib if, prior to testing, they have received 3 doses of vaccine (when immunization begins before age 6 months) or 2 doses (when immunization begins between 7 and 12 months of age).…”

The continuing role ofHaemophilus influenzaetype b carriage surveillance as a mechanism for early detection of invasive disease activity

“…[89][90][91] This paper presents summary information on additional medical or immunological risks based on the few publications available containing detailed risk information, from the UK, Canada and Alaska (US) ( Table 1). 20,53,57,92,93 Associated medical conditions reported for children experiencing true Hib country which does not offer routine Hib vaccination, indicated that Hib carriage commenced at age 3-5 mo, peaking at 18-21 mo. 58 Nasopharangeal carriage prior to three months is indicative of high risk or active infection, thus Hib carriage rates can serve as surrogate markers for disease occurrence and risk in some populations.…”