Antibody Concentrations Against the Infecting Serotype in Vaccinated and Unvaccinated ChildrenWith Invasive Pneumococcal Disease in the United Kingdom, 2006-2013

Nicholas Brousseau*, Nicholas Andrews, Pauline Waight, Elaine Stanford, Emma Newton, Rachael Almond, Mary P.E. Slack, Elizbeth Miller, Raymond Borrow, Shamez Ladhani

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Background. This study aimed to estimate, following invasive pneumococcal disease (IPD), the proportion of children with protective immunoglobulin G (IgG) concentrations against the infecting serotype compared with other vaccine serotypes, and to assess risk of recurrent IPD. Methods. Pneumococcal antibody concentrations were available for 413 children with vaccine-type IPD diagnosed during 2006-2013. We compared serotype-specific IgG concentrations against the infecting vs other vaccine serotypes, after adjusting for confounders such as age using multilevel analyses. Results. After IPD, a higher proportion of vaccine-naive children had IgG concentrations ≥0.35 μg/mL against their infecting serotype than other vaccine serotypes (51% vs 36%; P < .001). In contrast, among children immunized with pneumococcal conjugate vaccine (PCV) both before and after IPD, the proportion with IgG concentrations ≥0.35 μg/mL against the infecting serotype was lower compared with other vaccine serotypes (71% vs 98%; P < .001). These children also had lower IgG geometric mean concentrations (GMCs) against the infecting serotype (2.22 μg/mL) vs other vaccine serotypes (15.64 μg/mL) in multilevel models (IgG GMC ratio, 0.24; 95% confidence interval, .18-.32), although their IgG GMC was higher compared with vaccine-naive children. Vaccinated children with IgG concentrations <0.35 μg/mL against their infecting serotype generally remained unresponsive despite further vaccine doses. However, recurrent IPD with the same infecting serotype was rare (7/3030 children [0.2%]) and not associated with unresponsiveness. Conclusions. Vaccination with PCV before and/or after IPD was associated with lower IgG concentrations against the infecting serotype compared with other vaccine serotypes, but recurrent IPD was rare. Further studies are needed to understand this phenomenon in immunized children.

Original languageEnglish
Pages (from-to)1793-1801
Number of pages9
JournalClinical Infectious Diseases
Volume60
Issue number12
DOIs
Publication statusPublished - 15 Jun 2015

Keywords

  • Immunization
  • Immunoglobulin g
  • Invasive pneumococcal disease
  • Pneumococcal conjugate vaccine
  • Vaccination

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