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Pneumococcal antibodies in a child with type 14 pneumococcal conjugate vaccine failure

Katherine L O'Brien1, Jennifer Moïsi, Sandra Romero-Steiner

  • 1Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, 621 N, Washington St., Baltimore, MD, United States. klobrien@jhsph.edu

Vaccine
|January 28, 2009
PubMed

Insights

Antibody levels alone do not predict protection against pneumococcal infections. Functional activity and avidity also vary, indicating immune correlates are population-level insights, not individual guarantees.

Area of Science:

  • Immunology
  • Vaccinology
  • Pediatrics

Background:

  • Pneumococcal conjugate vaccines (PnCRM7) are crucial for preventing invasive pneumococcal disease (IPD).
  • Understanding individual immune responses post-vaccination is key to assessing vaccine efficacy.
  • Serotype 14 invasive pneumococcal disease (IPD) can occur despite vaccination.

Purpose of the Study:

  • To investigate antibody concentration, opsonic activity, and avidity in a vaccine failure case.
  • To compare immune responses in a patient with serotype 14 pneumococcal bacteremia to controls.

Main Methods:

  • Measured serotype-specific serum antibodies (concentration, opsonic activity, avidity) in a PnCRM7 vaccine recipient with IPD.
  • Compared antibody characteristics to control groups vaccinated with PnCRM7 or meningococcal conjugate vaccine (MnCC) without IPD.

Main Results:

  • The vaccine failure case had high antibody concentration but lower avidity compared to controls.
  • Antibodies in the case showed greater opsonic activity than controls.
  • The patient did not exhibit a booster response to a subsequent vaccine dose.

Conclusions:

  • Individual antibody concentration, opsonic activity, and avidity do not reliably predict protection against IPD.
  • Immunological correlates of protection are most meaningful at the population level, not for individual risk assessment.

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