Study of a 4-Dose Regimen of a 21-valent Pneumococcal Conjugate Vaccine in Healthy Infants From Approximately 2 Months of Age

Study Summary

This study is a Phase 3, randomized, modified double-blind study which aims to measure whether PCV21 vaccine (investigational pneumococcal conjugate vaccine) is safe and can help the body to develop germ-fighting agents called "antibodies" (immunogenicity) compared with 20-valent pneumococcal vaccine (Prevnar 20, licensed pneumococcal conjugate vaccine) when they are administered with routine pediatric vaccines in infants aged from approximately 2 months (42 to 89 days). The study duration per participant will be up to approximately 19 months. The study vaccines (either PCV21 or 20-valent pneumococcal vaccines) will be administered at approximately 2, 4, 6 and 12 to 15 months of age. Routine pediatric vaccines will be given at the same timepoints. There will be 6 study visits: -Visit (V)01, V02 separated from V01 by 60 days, V03 separated from V02 by 60 days, V04 separated from V03 by 30 days, V05 at 12 months of age until 15 months of age, V06 separated from V05 by 30 days.