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Comparison of pneumococcal vaccination response in children with sickle cell disease: HbSS and HbSC
X Le Ng1, M Alikhan1, J M Stark1
1Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA.
Insights
Children with HbSC sickle cell disease (SCD) show a better antibody response to pneumococcal vaccines than those with HbSS. Poor vaccine responders in SCD are at higher risk for pulmonary events.
Area of Science:
- Immunology
- Hematology
- Pediatrics
Background:
- Children with sickle cell disease (SCD) have an elevated risk of invasive pneumococcal disease.
- Penicillin prophylaxis and vaccination are crucial for infection prevention in SCD.
- Antibody levels after pneumococcal vaccination may decrease over time in SCD patients.
- Hemoglobin SC (HbSC) disease is hypothesized to elicit a superior immunological response compared to hemoglobin SS (HbSS) disease.
Purpose of the Study:
- To compare the antibody response to the 23-valent pneumococcal polysaccharide vaccine (PPSV-23) between patients with HbSS and HbSC.
- To assess the correlation between vaccine response and subsequent pulmonary events in SCD.
Main Methods:
- Prospective recruitment of pediatric patients with HbSS (n=33) and HbSC (n=11), aged 7-18 years.
- Administration of two doses of PPSV-23 to all participants.
- Measurement of Luminex pneumococcal antibody levels for 23 serotypes post-vaccination.
Main Results:
- HbSC patients exhibited higher median antibody titers for 20 out of 23 serotypes compared to HbSS patients, with significant differences for serotypes 22 and 43.
- While HbSC patients showed a trend towards a better immune response for 18 serotypes, it was not statistically significant.
- A higher percentage of HbSC patients (64%) were classified as good vaccine responders compared to HbSS patients (42%), though this difference was not significant (p=0.303).
- Poor vaccine responders in the SCD cohort had a significantly higher incidence of acute chest syndrome or pneumonia (39%) compared to good responders (10%) (p=0.036).
- None of the HbSC patients developed acute chest syndrome (ACS) post-vaccination.
- HbSS patients who were poor vaccine responders faced an increased risk of future ACS, pneumonia, or both compared to good responders.
Conclusions:
- HbSC patients demonstrate a more robust pneumococcal vaccine response than HbSS patients.
- Poor response to pneumococcal vaccination in SCD is a significant concern for future acute pulmonary complications.
- Current vaccination guidelines for different SCD subtypes may be inadequate, necessitating further research into the efficacy of vaccine boosters.
Introduction:
Sickle cell disease (SCD) children are at increased risk of invasive pneumococcal disease and rely on penicillin prophylaxis and vaccination for infection prevention. Post-vaccination antibody levels in SCD may wane overtime. HbSC are believed to have better immunological response than HbSS.
Objective:
To compare antibody response to 23-valent pneumococcal polysaccharide vaccine (PPSV-23) between HbSS and HbSC.
Methods:
Patients with HbSS (n=33) and HbSC (n=11), aged 7-18 years, were prospectively recruited. Luminex pneumococcal antibody levels were measured for 23-serotypes, after two PPSV-23 doses.
Results:
Absolute median titer for 20 of the 23 serotypes was higher in HbSC than HbSS and significantly higher for serotypes 22 (3.9 vs. 1.6mcg/ml; p=0.039) and 43 (2.9 vs. 0.8mcg/ml; p=0.007). HbSC mounted a better immune anti-pneumococcal response compared to HbSS (≥1.3mcg/ml) for 18 of 23 serotypes, albeit not significant for any of the serotypes. More HbSC (64%) than HbSS (42%) were good vaccine responders (p=0.303). Two of 21 (10%) good vaccine responders and nine of 23 (39%) poor vaccine responders SCD participants subsequently developed acute chest syndrome or pneumonia (p=0.036). None of the HbSC patients developed ACS after receiving PPSV-23. HbSS poor vaccine responders were at increased future recurrence risk for ACS (p=0.003), pneumonia (p=0.036) or both (p=0.011), compared to good vaccine responders.
Conclusion:
HbSC possess better pneumococcal vaccine response than HbSS. Poor vaccine response is concerning for future acute pulmonary events. Current vaccination strategy for SCD sub-types are lacking, therefore further study to evaluate utility of vaccine boosters is necessary.
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