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Serum opsonic activity after pneumococcal vaccination in splenectomized individuals as measured by a nitroblue
Insights
Children who had their spleen removed (splenectomized) and healthy siblings responded similarly to pneumococcal vaccination. However, vaccine-induced protection against pneumococcal infection may not be adequate for all types in all patients.
Area of Science:
- Pediatric immunology
- Vaccinology
- Infectious disease
Background:
- Splenectomized children are at increased risk of severe infections, particularly from encapsulated bacteria like Streptococcus pneumoniae.
- Pneumococcal vaccination is recommended for asplenic individuals to prevent pneumococcal disease.
- The effectiveness of pneumococcal vaccines in asplenic children requires ongoing evaluation.
Purpose of the Study:
- To assess the immunogenicity of a 14-valent pneumococcal vaccine (Pneumovax) in children who underwent splenectomy due to traumatic rupture.
- To compare the serum opsonic activity post-vaccination in splenectomized children versus healthy controls.
- To evaluate the durability of the immune response to pneumococcal vaccination over 12 months.
Main Methods:
- A cohort of 19 splenectomized children and 15 healthy siblings received a 14-valent pneumococcal vaccine.
- Serum opsonic activity against specific pneumococcal serotypes (3, 6A, 7F, 14, 19F, 23F) was measured before vaccination and at 2 and 12 months post-vaccination.
- A novel micromethod utilizing nitroblue tetrazolium reduction of granulocytes was employed to determine opsonic activity.
Main Results:
- Pre-vaccination, a higher prevalence of opsonic activity was observed in splenectomized children (38%) compared to controls (29%).
- Both splenectomized patients and healthy controls exhibited similar responses to the pneumococcal vaccine.
- Approximately 31% of both splenectomized children and controls showed a conversion from negative to positive serum opsonic activity after vaccination.
Conclusions:
- The 14-valent pneumococcal vaccine elicits a comparable immune response in splenectomized children and healthy siblings.
- Despite vaccination, the protective immunity against certain pneumococcal serotypes may be insufficient in some asplenic children.
- Further research is warranted to optimize pneumococcal vaccine strategies for asplenic pediatric populations.
Abstract:
19 children who were splenectomized after traumatic rupture and 15 healthy siblings were vaccinated with a 14-valent pneumococcal vaccine (Pneumovax). The serum opsonic activity against types 3, 6A, 7F, 14, 19F and 23F was evaluated before the vaccination and after 2 and 12 months by a new micromethod based on nitroblue tetrazolium reduction of granulocytes. Before the vaccination, opsonic activity was found more often in the splenectomized than in the controls, 38 and 29%, respectively. However, patients and controls responded similarly to the vaccine. The serum opsonic activity changed from negative to positive after vaccination in 31% of the splenectomized, as well as the controls. The results indicate that the protection against pneumococcal infection after vaccination may not be adequate against all pneumococcal types in all patients.