Dynamics of the Immune Response in Children to the 23-valent Pneumococcal Capsular Polysaccharide Vaccine (Pneumovax)

To explore a further dimension of susceptibility to disease, the investigators tested the hypothesis that natural variation exists in the rapidity of IgG responses following exposure to pneumococcal polysaccharides, and that these differences are sufficiently great to affect susceptibility to and outcome of IPD. The study recruited children aged 24-36 months, who had recovered from IPD, and age-matched healthy controls and vaccinated them with 1 dose of the 23-valent PPV to mimic natural exposure. The investigators collected serum samples after vaccination and analysed the dynamics of anti-polysaccharide antibody responses to several capsular antigens.