This study is testing a new vaccine called PCV21 for infants aged about 2 months. Pneumococcal conjugate vaccines protect against infections caused by the Streptococcus pneumoniae bacteria. The study compares PCV21 with an existing 20-valent vaccine, meaning the vaccine targets 20 types of bacteria. It is a Phase 3 trial, which means the vaccine has already been tested in earlier stages for safety.

Participants will be involved for about 19 months. The vaccine is given at 2, 4, 6, and 12-15 months. There will be a total of 6 study visits. Participation requires being healthy, born at full term or slightly early, and stable. Infants with certain medical conditions or past vaccinations may not be eligible.

• Study lasts about 19 months with 6 visits.
• Vaccine given at specific ages: 2, 4, 6, and 12-15 months.
• Participants need to be healthy and born full-term or slightly early.

Always discuss with a healthcare provider to understand if joining a study is the right choice for your child.