Maternal pneumococcal conjugate immunization protects infant chinchillas in the pneumococcal otitis media model

Infant immunization with pneumococcal polysaccharide-protein conjugate vaccines (PCVs) is unlikely to elicit protective serum antibody, concentrations during the first 4-6 months of life. when recurrent pneumococcal otitis media (POM) often begins. We therefore investigated a maternal pneumococcal immunization strategy to present earls infant POM, Pregnant chinchillas (clams) received injections of heptavalent PCV or saline, Post-partum maternal and infant (kits) blood samples were obtained. and kits were subsequently challenged b intranasal inoculation Of a vaccine-type pneumococcal strain (19F). Anti-pneumococcal capsular polysaccharide IgG antibody (Ab) concentration was, measured using an ELISA in maternal and kit serum samples, Immunized dams and their kits had significantly higher Ab titers than control dams and their kits. Antibody titer in kits declined kith a half-life of 12 days, Maternal immunization significantly reduced both the incidence (p = 0.05) and severity (p < 0.01) of experimental POM in chinchilla kits, and k as 82", at preventing mortality from invasive pneumococcal disease. Pre-challenge serum Ab concentration in kits was the jingle best predictor of POM severity (r = -0.66). This experiment strongly Supports the h pathogenesis that maternal immunization with PCV will reduce the burden of early infant POM and invasive pneumococcal disease.