title: Conjugate Haemophilus influenzae type b vaccines for sickle cell disease.
abstract: BACKGROUND
  People affected with sickle cell disease are at high risk of infection from Haemophilus influenzae type b. Before the implementation of Haemophilus influenzae type b conjugate vaccination in high-income countries, this was responsible for a high mortality rate in children under five years of age. In African countries, where coverage of this vaccination is still extremely low, Haemophilus influenzae type b remains one of the most common cause of bacteraemias in children with sickle cell disease. The increased uptake of this conjugate vaccination may substantially improve the survival of children with sickle cell disease.
  
  
  OBJECTIVE
  The primary objective was to determine whether Haemophilus influenzae type b conjugate vaccines reduce mortality and morbidity in children and adults with sickle cell disease.The secondary objectives were to assess the following in children and adults with sickle cell disease: the immunogenicity of Haemophilus influenzae type b conjugate vaccines; the safety of these vaccines; and any variation in effect according to type of vaccine, mode of administration (separately or in combination with other vaccines), number of doses, and age at first dose.
  
  
  METHODS
  We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also contacted relevant pharmaceutical companies to identify unpublished trials.Date of last search: 23 November 2015.
  
  
  METHODS
  All randomised and quasi-randomised controlled trials comparing Haemophilus influenzae type b conjugate vaccines with placebo or no treatment, or comparing different types of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease.
  
  
  METHODS
  No trials of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease were found.
  
  
  RESULTS
  There is an absence of evidence from randomised controlled trials relating to the subject of this review.
  
  
  CONCLUSIONS
  There has been a dramatic decrease in the incidence of invasive Haemophilus influenzae type b infections observed in the post-vaccination era in people with sickle cell disease living in high-income countries. Therefore, despite the absence of evidence from randomised controlled trials, it is expected that Haemophilus influenzae type b conjugate vaccines may be useful in children affected with sickle cell disease, especially in African countries where there is a high prevalence of the disease. The implementation of childhood immunisation schedules, including universal Haemophilus influenzae type b conjugate vaccination, may substantially improve the survival of children with sickle cell disease living in low-income countries. We currently lack data to evaluate the potential effect of Haemophilus influenzae type b vaccination among unvaccinated adults with sickle cell disease. Further research should assess the optimal Hib immunisation schedule in children and adults with sickle cell disease.
authors.affiliation: Department of General Pediatrics, Necker Hospital for Sick Children, 149 rue de Sevres, Paris, France, 75015.
authors.forename: Slimane
authors.initials: S
authors.lastname: Allali
authors.forename: Martin
authors.initials: M
authors.lastname: Chalumeau
authors.forename: Odile
authors.initials: O
authors.lastname: Launay
authors.forename: Samir K
authors.initials: SK
authors.lastname: Ballas
authors.forename: Mariane
authors.initials: M
authors.lastname: de Montalembert
mesh_terms: D000755:Anemia, Sickle Cell / Q000150:complications*; D016667:Bacterial Capsules / Q000276:immunology; D006192:Haemophilus Infections / Q000517:prevention & control*; D018073:Haemophilus Vaccines / Q000008:administration & dosage* / Q000276:immunology; D019741:Haemophilus influenzae type b / Q000276:immunology*; D006801:Humans; D018074:Vaccines, Conjugate / Q000008:administration & dosage
chemical_list: D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D018074:Vaccines, Conjugate