Safety, tolerability, and immunogenicity of 7-valent pneumococcal conjugate vaccine in older infants and young children in China who are naive to pneumococcal vaccination: Results of a phase 4 open-label trial.

Abstract Background This postlicensure study was conducted to assess immunogenicity and safety of PCV7 catch-up regimens in previously unvaccinated older infants and young children in China. Methods Healthy children 121 days to Results Prevaccination serotype-specific GMCs were generally low in subjects 90% of subjects had IgG ≥ 0.35 μg/mL for each PCV serotype. At 12-month follow-up, IgG GMCs ranged from 0.65 to 5.19, and all remained above prevaccination IgG GMC; >70% of subjects had IgG ≥ 0.35 μg/mL. Older children generally had the most robust immune response both at 1 month postvaccination and during 12-month follow-up. PCV7 was well tolerated. Pyrexia, which was mild to moderate in severity, was the most common AE. Two subjects reported SAEs ( n  = 4), and there was 1 study withdrawal; none of these were considered treatment related. Conclusion In China, PCV7 catch-up vaccinations given to older infants and young children naive to pneumococcal vaccines resulted in a robust immune response to all serotypes; this response persisted after 1 year. PCV7 was well tolerated in Chinese infants and children.