Streptococcus pneumoniae Antibodies, IgG (23 Serotypes)

A pre- and post-vaccination comparison is required to adequately assess the humoral immune response to Prevnar 7 (P7), Prevnar 13 (P13), and/or Pneumovax 23 (PNX) Streptococcus pneumoniae vaccines. Pre-vaccination samples should be collected prior to vaccine administration. Post-vaccination samples should be obtained at least 4 weeks after immunization. Testing of post-vaccination samples alone will provide only general immune status of the individual to various pneumococcal serotypes.

In the case of pure polysaccharide vaccine, indication of immune system competence is further delineated as an adequate response to at least 50 percent of the serotypes in the vaccine challenge for those 2-5 years of age and to at least 70 percent of the serotypes in the vaccine challenge for those 6-65 years of age. Individual immune response may vary based on age, past exposure, immunocompetence, and pneumococcal serotype.

Responder Status                         Antibody Ratio
Non-Responder . . . . . . . . . . . . . . Less than 2-fold
Weak Responder . . . . . . . . . . . . . 2-fold to 4-fold
Good Responder . . . . . . . . . . . . . Greater than 4-fold

A response to 50-70 percent or more of the serotypes in the vaccine challenge is considered a normal humoral response¹. Antibody concentration greater than 1.0 - 1.3 µg/mL is generally considered long-term protection².

References:
1. Daly TM, Pickering JW, Zhang X, Prince HE, Hill HR. Multilaboratory assessment of threshold versus fold-change algorithms for minimizing analytical variability in multiplexed pneumococcal IgG measurements. Clin Vaccine Immunol. 2014;21(7):982-8.
2. Daly TM, Hill HR. Use and Clinical Interpretation of Pneumococcal Antibody Measurements in the Evaluation of Humoral Immune Function. Clin Vaccine Immunol. 2015;22(2):148-152.