Pneumococcal conjugated vaccine: PHiD-CV.

At the beginning of a new century, we have gained significant achievements against pneumococcal infections by using conjugated pneumococcal vaccines. In January 2009, the EMEA issued a positive opinion about, and recommended the approval of, GlaxoSmithKline's pediatric pneumococcal candidate vaccine, which is indicated for active immunization against invasive pneumococcal disease (IPD) and acute otitis media caused by Streptococcus pneumoniae in infants and children from 6 weeks up to 2 years of age. The approved 10-valent pneumococcal vaccine (PHiD-CV) contains all serotypes in 7-valent pneumococcal conjugate vaccine (PCV-7) plus serotypes 1, 5 and 7F. Protein D from nontypeable Haemophilus influenzae is the carrier protein for eight serotypes, while tetanus and diphtheria toxins are in the carrier proteins for the remaining two serotypes. It has also been proved that PHiD-CV is immunogenic, safe and well-tolerated in children. This vaccine can be coadministered with routinely used pediatric vaccines. Noninferiority criteria of PHiD-CV compared with PCV-7 were established in shared serotypes, except for serotypes 6B and 23F, and PHiD-CV is immunogenic for additional serotypes as assessed by the percentage of subjects with antibody concentrations. PHiD-CV is also immunogenic for ten serotypes as assessed by post-primary and post-booster dose opsonophagocytic activity responses. Vaccine efficacy against IPD and other conditions should be monitored for shared serotypes and also additional serotypes during the postmarketing period. Optimal scheduling, safety and immunogenicity data in children with different risk factors for IPD, or whether it will provide herd immunity, are the questions waiting for answers in the postmarketing period. Further studies are needed to assess the potential advantages of protein D as a carrier and the potential efficacy of this new vaccine against H. influenzae. The potential public health efficacy of PHiD-CV in low-income countries, where IPD and pneumonia are a major public health problem, is a major concern.