Safety and immunogenicity of 13-valent pneumococcal conjugate vaccine in infants: a meta-analysis

Pneumococcal infections are a major cause of morbidity and mortality worldwide. Pneumococcal conjugate vaccines represent major progress in the prevention of invasive pneumococcal disease in the paediatric population. We performed a meta-analysis, in accordance with the PRISMA statement, in order to assess the immunogenicity and safety of 13-valent pneumococcal conjugate vaccines in infants. A literary search was conducted using electronic databases and specialized journals were searched manually. Inclusion criteria were: clinical trials with infants vaccinated with 13-valent pneumococcal conjugate, compared to 7-valent vaccine. We recorded the results in terms of the immunogenicity and safety of the vaccines. The quality of the studies included was assessed using the CASP and Jadad checklists. We included nine randomized clinical trials of 258 potentially relevant references in the meta-analysis. The studies included had high-moderate quality. Both vaccines were well tolerated in all groups of infants, and most local reactions and systemic events were of mild or medium intensity and typical of any injected vaccine. All studies included in the meta-analysis showed high immunogenicity for both pneumococcal vaccines in all tested serotypes. An anti-polysaccharide antibody concentration of ≥0.35 μg/mL was achieved in at least 89% of the infants. Our results suggest that the 13-valent pneumococcal conjugate vaccine has a similar safety profile, and is as effective as, the 7-valent vaccine in the prevention of invasive pneumococcal disease caused by the seven common serotypes, and could provide expanded protection against the six additional serotypes.