Immune response in infants to the heptavalent pneumococcal conjugate vaccine against vaccine-related serotypes 6A and 19A

Hyunju Lee, Moon H. Nahm, Robert Burton, Kyung Hyo Kim

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

The currently available 7-valent pneumococcal conjugate vaccine (PCV7) elicits good immune response to and is effective against vaccine serotypes. However, its effectiveness against vaccine-related serotypes is variable. Serum samples were obtained 1 month after the last vaccination from 31 infants immunized with PCV7 at 2, 4, and 6 months of age. The sera were used to determine immunoglobulin G antibody levels to eight serotypes (seven vaccine serotypes and serotype 19A) with enzyme-linked immunosorbent assay (ELISA) and opsonic capacity against 11 serotypes (seven vaccine serotypes, serotypes 19A and 6A, and nonvaccine serotypes 5 and 7F) using a multiplexed opsonization assay. ELISA results showed antibody concentrations varied between 1.84 and 10.49 μg/ml, and all subjects had antibody concentrations of ≥0.35 μg/ml for all serotypes, including serotype 19A. In contrast, the opsonic index was detectable (i.e., opsonic index ≥ 8) in all children for the seven vaccine serotypes, 81% for serotype 6A, and merely 19% for serotype 19A. PCV7 shows good immunogenicity for vaccine serotypes in infants after a primary series. PCV7 does not elicit opsonic antibodies to serotype 19A. ELISA may thus be an inadequate surrogate assay for evaluating the response for crossreactive serotypes in infants.

Original languageEnglish
Pages (from-to)376-381
Number of pages6
JournalClinical and Vaccine Immunology
Volume16
Issue number3
DOIs
StatePublished - Mar 2009

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