Antibody responses to Haemophilus influenzae type b conjugate vaccine in sickle cell disease.
OBJECTIVE
To investigate the immunogenicity of Haemophilus influenzae type b (Hib) conjugate vaccines in children with sickle cell disease.


METHODS
Open study.


METHODS
Haemoglobinopathy clinic.


METHODS
Children with homozygous haemoglobin SS disease (HbSS), sickle haemoglobin C disease (HbSC), and sickle-beta thalassaemia disease (HbS-beta Thal).


METHODS
Children over the age of 2 years received a single dose of Hib-tetanus toxoid conjugate vaccine (PRP-T).


METHODS
Antibody response to Hib polysaccharide (PRP) approximately one month after vaccination.


RESULTS
77 children over the age of 2 years were studied,, 55 with HbSS, 16 with HbSC, and six with HbS-beta Thal. Before vaccination, 44% had anti-PRP IgG titres less than the level associated with long term protection (1.0 microgram/ml). After a single dose of PRP-T all children mounted an antibody titre > 1 microgram/ml. Geometric mean anti-PRP IgG titre achieved postvaccination (45.2 micrograms/ml 95% confidence interval (CI) 31.6 to 64.8) was comparable to that of a healthy population. Children with HbSC, however, had a significantly higher antibody titre postvaccination (91.1 micrograms/ml; 95% CI 32.7 to 254.4) than the children with HbSS (36.7 micrograms/ml; 95% CI 25.1 to 52.9).


CONCLUSIONS
Children with a diagnosis of sickle cell disease who are over the age of 2 years make a vigorous antibody response to a single dose of PRP-T vaccine and hence we suggest unimmunised individuals in this group should receive a single dose of a Hib conjugate vaccine.
Goldblatt
D
D
Immunobiology Unit, Institute of Child Health, London.
Johnson
M
M
Evans
J
J
D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000276:immunology*; D000914:Antibodies, Viral / Q000096:biosynthesis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D018073:Haemophilus Vaccines / Q000276:immunology*; D006193:Haemophilus influenzae / Q000276:immunology*; D006450:Hemoglobin SC Disease / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D008297:Male; D017086:beta-Thalassemia / Q000276:immunology
D000914:Antibodies, Viral; D018073:Haemophilus Vaccines; D007074:Immunoglobulin G