It has been suggested that
otitis-prone children have an impaired antibody response. To investigate this in the context of pneumococcal vaccination, we used a multiplex bead-based assay to measure serum
IgG and
IgA levels against pneumococcal serotypes included in the 7-valent pneumococcal
conjugate vaccine (PCV7; serotypes 4, 6B, 9V, 14, 18C, 19F and 23F) and 4 non-PCV7 serotypes (1, 5, 7F and 19A) in healthy (n=43) and
otitis-prone children (n=75) before, 6 weeks after and 1 year after vaccination with one dose of PCV7. Pre-vaccination,
otitis-prone children had significantly higher serum
IgG levels against serotypes 4, 9V and 23F and against all non-PCV7 serotypes. One year following vaccination, there was no difference in
IgG or
IgA levels between healthy and
otitis-prone children. The effect of the administration of one or two doses of PCV7 was investigated in
otitis-prone children. After a second dose of PCV7, pneumococcal serotype specific
IgG levels, but not
IgA titres, were higher compared to the levels measured after the initial dose of PCV7. One year post PCV7 vaccination there was no difference in either
IgG or
IgA antibody levels to any of the PCV7 serotypes between children who received either one or two doses of PCV7. The finding that
otitis-prone children do not have an impaired pneumococcal serotype-specific serum
IgG or
IgA response suggests that new pneumococcal
conjugate vaccines may be immunogenic in
otitis-prone children, however, further investigations are necessary to determine the clinical impact of such
vaccines against the development of recurrent acute
otitis media.