Quantitative Methods for Evaluating Antibody Responses to Pneumococcal Vaccines: A Scoping Review

Area of Science:

• Immunology
• Vaccinology
• Biotechnology

Background:

• Streptococcus pneumoniae causes invasive diseases, especially in children and the elderly.
• Current vaccines like PPSV23 and PCV20 target specific serotypes, but immune responses vary.
• Quantitative antibody assessment methods are crucial for evaluating vaccine effectiveness.

Purpose of the Study:

• To systematically review quantitative immunoassays for assessing antibody responses to pneumococcal vaccines.
• To summarize conventional and novel methods, evaluate their validation and application, and identify knowledge gaps.

Main Methods:

• A scoping review following PRISMA-ScR guidelines.
• Searched PubMed and Scopus for peer-reviewed articles (2000-2023) on pneumococcal antibody immunoassays.
• Included 55 articles after screening for eligibility.

Main Results:

• Early methods like radioimmunoassays were replaced by ELISA, the current gold standard but with limitations.
• Multiplex immunoassays (MIAs) offer efficiency and scalability but often lacked initial validation.
• Recent assays show improved performance, yet interlaboratory variability and lack of standardized protective thresholds persist.

Conclusions:

• This review comprehensively maps quantitative antibody assessment methods for pneumococcal vaccines.
• While ELISA is a benchmark, MIAs are a promising next-generation approach.
• Harmonizing validation protocols and establishing global standards for protective thresholds are essential for reliable vaccine monitoring.