Pneumococcal polysaccharide protein D-conjugate vaccine (Synflorix; PHiD-CV)

The pneumococcal polysaccharide protein D-conjugate vaccine (PHiD-CV; Synflorix) contains ten capsular polysaccharide serotypes from the bacterium Streptococcus pneumoniae, eight of which are conjugated to a nonlipidated cell-surface liporotein (protein D) of non-typeable Haemophilus influenzae (NTHi) and two of which are conjugated to either tetanus or diphtheria toxoid. In a three-dose primary vaccination schedule in infants aged <6 months, PHiD-CV elicited high immune responses against all pneumococcal serotypes contained in the vaccine and was noninferior to an approved 7-valent pneumococcal conjugate vaccine (7vCRM) for eight of the ten serotypes (five of the seven common to both vaccines). Moreover, functional antibodies were elicited against all vaccine serotypes in an opsonophagocytic activity (OPA) assay. A fourth booster dose of PHiD-CV during the second year of life elicited an anamnestic response against all ten pneumococcal serotypes, as determined by both antibody concentrations and OPA titers. There were no clinically relevant changes in the immunogenicity of PHiD-CV when coadministered with meningococcal serogroup C conjugate or pentavalent whole cell pertussis combination vaccines, and polio vaccines using two different primary vaccination schedules. 11Pn-PD, an 11-valent prototype of PHiD-CV, demonstrated protection against episodes of acute otitis media (AOM) caused by S. pneumoniae and NTHi in infants aged <27 months. The first occurrence of an episode of AOM caused by pneumococcal vaccine serotypes was reduced by 52.6% in 11Pn-PD vaccinees compared with recipients of a control vaccine (primary endpoint). The tolerability profile of PHiD-CV was generally similar to that of 7vCRM.