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Immunization of children with sickle cell disease with Haemophilus influenzae type b polysaccharide vaccine
L G Rubin1, D Voulalas, L Carmody
1Division of Infectious Diseases, Schneider Children's Hospital of Long Island Jewish Medical Center, New Hyde Park, NY 11042.
Insights
The Haemophilus influenzae type b polysaccharide vaccine was safe and generally well-tolerated in children with sickle cell disease. However, immunogenicity varied, with younger children showing a less robust antibody response to the Hib vaccine.
Area of Science:
- Pediatrics
- Immunology
- Hematology
Background:
- Limited data exist on the safety and immunogenicity of Haemophilus influenzae type b (Hib) polysaccharide vaccine in pediatric sickle cell disease (SCD) patients.
- Sickle cell disease compromises immune function, increasing susceptibility to encapsulated bacteria like Hib.
Purpose of the Study:
- To evaluate the safety and immunogenicity of the Hib polysaccharide vaccine in children with sickle cell disease.
- To assess antibody responses to the Hib vaccine across different age groups within the SCD population.
Main Methods:
- Ninety-eight children with SCD (SS, SC, S beta-thalassemia) aged 1.5–20 years received a 25 microgram subcutaneous dose of Hib polysaccharide vaccine.
- Safety was monitored for adverse events, and immunogenicity was assessed by measuring anticapsular antibody concentrations via radioimmunoassay before and 1–2 months after vaccination.
Main Results:
- The vaccine was well-tolerated, with mild side effects in 6.1% of patients. One hospitalization occurred due to fever and vaso-occlusive crisis post-vaccination.
- Pre-vaccination antibody levels were low in younger children (18-24 months and 2-5 years).
- Inadequate antibody response ( < 1 microgram/mL) 1–2 months post-vaccination was observed in 60% of 18–24 month olds, 32% of 2–5 year olds, and 4% of 6–20 year olds.
Conclusions:
- The Hib polysaccharide vaccine is safe for children with sickle cell disease.
- Younger children (under 5 years) with SCD demonstrate lower immunogenicity and a higher rate of inadequate antibody response to the Hib polysaccharide vaccine.
- Further investigation may be needed to optimize vaccination strategies for young children with SCD to ensure adequate protection against Hib infections.
Abstract:
There are limited data concerning safety and immunogenicity of Haemophilus influenzae type b polysaccharide vaccine in children with sickle cell disease. Ninety-eight patients with sickle cell disease (65 with SS phenotype, 23 with SC phenotype, and 10 with S beta-thalassemia) 1.5 to 20 years of age were given 25 micrograms of vaccine subcutaneously. The vaccine was well tolerated; mild side effects were observed in 6 of 98 (6.1%) children. In addition, one patient with a recent vasoocclusive crisis was hospitalized because of fever and vasoocclusive crisis 8 hours after vaccination. Prevaccination anticapsular antibody concentrations (by radioimmunoassay) were less than 0.15 microgram/mL in 7 of 11 children 18 to 24 months of age (geometric mean 0.17 microgram/mL), in 10 of 25 children 2 to 5 years of age (geometric mean 0.36 microgram/mL), and in 3 of 50 patients 6 to 20 years of age (geometric mean 1.03 microgram/mL). Inadequate response (1- to 2-month postvaccination antibody level less than 1 microgram/mL) was found in 3 of 5 children 18 to 24 months of age (geometric mean 1.74 microgram/mL), in 8 of 21 children 2 to 5 years of age (geometric mean 2.20 micrograms/mL), and in 2 of 49 patients 6 to 20 years of age (geometric mean 18.03 micrograms/mL). Six months after vaccination, greater than 1 microgram/mL of antibody was present in the 2 children 6 to 20 years of age with inadequate response but not in the 7 children 2 to 5 years of age with inadequate response.(ABSTRACT TRUNCATED AT 250 WORDS)