Pneumococcal Immunization

This is a phase 3 randomized, modified double-blind study whose purpose is to measure whether 3 lots of the investigational pneumococcal vaccine PCV21 can help the body to develop germ-fighting agents called "antibodies" (immunogenicity) in a similar way (ie, same immune response) when they are given to infants aged from approximately 2 months (42 to 89 days) and are safe compared to a licensed 20-valent pneumococcal vaccine (20vPCV) (Prevnar 20™). The study duration per participant will be up to approximately 17 months. The study vaccines (either PCV21 or 20vPCV) will be administered at approximately 2, 4, 6 and 12 months of age. Cohort A will include randomization to three PCV21 formulation groups or one 20vPCV comparator group (Group 1-4, approximately 896 total participants), whereas Cohort B will include randomization to three PCV21 formulation groups only (Groups 1-3, approximately 1299 total participants). Routine pediatric vaccines will be given as per local recommendations. 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, V06 separated from V05 by 30 days

The purpose of this study is to understand the safety of Prevenar 20 (Pneumococcal 20-valent conjugate vaccine) once it is out in the Korean market. Prevenar 20 will be given to participants aged 6 weeks or older in Republic of Korea. This study is seeking for participants who are: * Infant, children and adolescents aged 6 weeks to under 18 years or adult who are 18 years or older * Prescribed Prevenar 20 by their physician as per approved product label All participants in this study will receive Prevenar 20 vaccine. 1 dose (0.5 mL) of Prevenar 20 will be given into a muscle, preferably to the shoulder muscle. We will look at the experiences of people receiving the study medicine. This will help us see if the study medicine is safe. Participants will take part in this study for 28 days. During this time, study doctor collects the data of subjects to understand the safety of study medicine. There is no strict fixed visit schedule. If subjects are unable to visit the study clinic 28 days after Prevenar 20 vaccine was given then the safety information will be collected by telephone or e-mail.