Reduction of antibody response to an 11-valent pneumococcal vaccine coadministered with a vaccine containing acellular pertussis components.

In pneumococcal conjugate vaccines (PCVs), polysaccharide antigens are often conjugated to protein carriers related to other common vaccines. It is therefore important to test PCV interaction with other pediatric vaccines when administered simultaneously. We assessed the immune response to an 11-valent PCV conjugated to diphtheria and tetanus carriers (PncD/T11), administered concomitantly, but in separate sites, with a combined vaccine containing epitopes related antigenically to the carriers: polyribosylribitol phosphate-tetanus tox oid (PRP-T), diphtheria toxoid (DT), and tetanus toxoid (TT). In addition, these combinations contained inactivated poliovirus vaccine (IPV) and either whole-cell pertussis (wP) or acellular pertussis (aP) components. After coadministration of PncD/T11 with the combined vaccine containing wP (DTwP/IPV/PRP-T), the responses to all polysaccharides in the PncD/T11 were satisfactory. In contrast, when coadministered with an aP-containing combination (DTaP/IPV/PRP-T), the response to all seven pneumococcal conjugates to TT was significantly reduced after primary and booster immunization. The pneumococcal conjugates to DT were not significantly reduced after the primary series, but were somewhat reduced after booster. It is likely that some suppression of the tetanus-mediated response occurred even when the PncD/T11 was coadministered with wP, but this suppression was masked by the adjuvant effect of wP. By replacing wP with aP, this adjuvant effect was removed, unmasking the suppression of the tetanus-mediated response. With the increasing use of multiple aP-containing vaccines in infancy, novel approaches to adjuvants and carrier protein technology are likely to be required.