A comparison of multiple regimens of pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine and pneumococcal polysaccharide vaccine in toddlers.

Children who had been randomized to receive one dose of either heptavalent pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine (PCV) or 23-valent pneumococcal polysaccharide vaccine (PN23) at 12, 15, or 18 months of age were subsequently randomized to receive a booster injection of either PCV or PN23 12 months later. For those children who received a priming dose of PCV (N=75) compared to PN23 (N=48) at 12, 15, or 18 months of age, higher serum antibody concentrations were achieved 1 month following a booster injection of either PCV or PN23 for all serotypes tested (p<0.001). Within the group of children receiving a priming dose of PCV, those children who received a booster dose of PN23 developed higher serum antibody concentrations for four of the seven serotypes tested and similar opsonic antibody titers to serotype 6B, yet more frequent erythema (p=0.030) and pain or soreness (p=0.024) at the injection site compared to those boosted with PCV. In conclusion, a single dose of PCV at 12-18 months of age primed for responses to booster doses of either PCV or PN23 12 months later. For those children who received a priming dose of PCV, boosting with PN23 resulted in more frequent injection site pain and erythema than boosting with PCV, yet higher antibody concentrations for most of the serotypes tested.