Related Experiment Videos
Pneumococcal polysaccharide immunization of children with sickle cell disease. II. Serologic response and
Insights
Children with sickle cell disease (SCD) showed varied antibody responses to a pneumococcal vaccine. Older children had better responses, suggesting age impacts vaccine effectiveness in SCD patients.
Area of Science:
- Immunology
- Pediatrics
- Vaccinology
Background:
- Sickle cell disease (SCD) increases susceptibility to encapsulated bacteria, particularly Streptococcus pneumoniae.
- Pneumococcal vaccination is crucial for preventing invasive pneumococcal disease in children with SCD.
- The immunogenicity of pneumococcal vaccines in children with SCD requires careful evaluation.
Purpose of the Study:
- To assess the antibody response to a tetradecavalent pneumococcal vaccine in children with SCD.
- To characterize the influence of age on vaccine response in this population.
- To evaluate the vaccine's potential efficacy in preventing pneumococcal infections.
Main Methods:
- 174 children with SCD received a single dose of the tetradecavalent pneumococcal vaccine.
- Antibody titers against 13 pneumococcal capsular antigens were measured pre- and post-immunization using indirect hemagglutination (IHA).
- Response patterns were categorized based on antigen type and age at immunization.
Main Results:
- Antibody responses varied by capsular antigen type, with some showing poor response (6A, 14, 19F) and others good response (2, 3, 7F, 8) regardless of age.
- Responses to certain antigens (1, 4, 9N, 12F, 18C, 23F) improved with increasing age at immunization.
- A significant correlation was found between pre- and post-immunization antibody titers (P < 0.0005).
- Two cases of pneumococcal sepsis occurred in children under 24 months, and one in an older child, suggesting limited protection from a single dose.
Conclusions:
- Age significantly influences the antibody response to pneumococcal vaccination in children with SCD.
- Anamnestic immune responses likely contribute to better antibody levels in older children.
- A single dose of this pneumococcal vaccine may offer only modest efficacy in children with SCD.
Abstract:
One-hundred seventy-four children with sickle cell disease (SCD) were immunized with a single dose of tetradecavalent pneumococcal vaccine. Preimmunization and postimmunization antibody against 13 of the 14 pneumococcal capsular antigens was measured by indirect hemagglutination (IHA). The ability of each antigen to stimulate antibody following immunization was characterized by one of three types of responses: (1) poor antibody response regardless of the age at immunization (capsular types 6A, 14, and 19F); (2) improving antibody response with advancing age at immunization (capsular types 1, 4, 9N, 12F, 18C, and 23F); and (3) good antibody response regardless of age at immunization (capsular types 2, 3, 7F, and 8). An increase in antibody following immunization was significantly correlated (P less than 0.0005) with an increasing level of preimmunization antibody titer for all 13 antigens. Through the first 24 months of study, two episodes of pneumococcal sepsis caused by group 23 pneumococci were documented in two children immunized prior to 24 months of age (incidence rate, 4.40/100 patient-years in children less than 5 years of age), and one additional episode caused by a group 23 pneumococcus occurred in a 5 7/12-year-old child (incidence rate, 0.66/100 patient-years in children greater than 5 years of age). These observations suggest that anamnestic immune response significantly contributed to the enhanced antibody response observed in older children and adults. Only modest vaccine efficacy may be expected among children with SCD who receive a single dose of pneumococcal vaccine.