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Updated: Jun 29, 2025
Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
Potential serotype-specific effectiveness against IPD of pneumococcal conjugate vaccines V114 and PCV20 in children
Josiah Ryman1, Jeffrey R Sachs1, Natalie Banniettis2
1Quantitative Pharmacology and Pharmacometrics, Merck & Co Inc, Rahway, NJ, USA.
Insights
New pneumococcal conjugate vaccines (PCVs) V114 and PCV20 show varied effectiveness. V114 is predicted to be more effective than PCV20 against common pneumococcal serotypes, especially serotype 3.
Area of Science:
- Immunology
- Vaccinology
- Epidemiology
Background:
- Next-generation pneumococcal conjugate vaccines (PCVs) are evaluated by comparing immune responses to existing standard-of-care PCVs.
- This ensures vaccine efficacy for preventing pneumococcal disease across shared serotypes.
Purpose of the Study:
- To predict the serotype-specific vaccine effectiveness (VE) of V114 and PCV20.
- To compare their effectiveness against PCV13 for shared serotypes in a pediatric population using a 2+1 dosing regimen.
Main Methods:
- Utilized a qualified method to predict serotype-specific VE against invasive pneumococcal disease.
- Focused on serotypes shared with PCV13 in EU, Russian, and Australian pediatric populations.
Main Results:
- V114 demonstrated predicted VE ranging from 79% to 100%, comparable to PCV13, with higher predicted effectiveness against serotype 3 (93% vs. 65%).
- PCV20 showed predicted VE from 47% to 91%, but lower effectiveness than PCV13 for several key serotypes (4, 19F, 23F, 1, 3, 5, 6A, 7F, 19A).
Conclusions:
- V114 is predicted to be more effective than PCV20 against PCV13 serotypes with a 2+1 dosing regimen, particularly for serotype 3.
- Real-world studies are essential to confirm these predicted VE values and refine modeling for novel PCVs.
Background:
Next generation, higher valency pneumococcal conjugate vaccines (PCVs) are assessed and licensed by comparing the immune response across serotypes shared with the PCVs that are standard of care for prevention of pneumococcal disease.
Methods:
Using a previously qualified method we predicted the serotype-specific vaccine effectiveness (VE) against invasive pneumococcal disease of V114 and PCV20 for the serotypes shared with PCV13 in an EU, Russian, and Australian pediatric population that is recommended to receive a 2 + 1 dosing regimen.
Results:
The estimated protective antibody concentrations ranged from 0.03 (serotype 23F) to 1.49 µg/mL (serotype 19F). Predicted VE values for V114 ranged from 79% (serotype 5) to 100% (serotype 23F). V114 had comparable effectiveness to PCV13 for all but one of shared serotypes, with predicted higher effectiveness (in V114) against serotype 3 (93% vs. 65%). Predicted VE values for PCV20 ranged from 47% (serotype 3) to 91% (serotype 14). PCV20 predicted VE was lower than PCV13's for serotypes 4, 19F, 23F, 1, 3, 5, 6A, 7F, and 19A.
Conclusions:
Predicted serotype-specific VE values suggest that, with a 2 + 1 dosing regimen, V114 will have greater effectiveness than PCV20 against PCV13 serotypes, particularly for the still-prevalent serotype 3. Real-world VE studies will ultimately provide clarity on the effectiveness of novel PCVs and support further confidence in and/or improvements to modeling efforts.
