A Study to Evaluate the Immunogenicity and Safety of 13-valent Pneumococcal Conjugate Vaccine (PCV13i) in Healthy Infants Aged 2 Months (Minimum 6 Weeks)

Inclusion Criteria: * Healthy infants with stable clinical conditions aged 2 months (42-90 days) at the time of screening, based on medical history and clinical assessment by the investigator. Infants will be eligible starting from the day they turn 6 weeks of age. * Infant's parent or legal guardian must be able and willing to provide informed consent for the infant's participation in the study. * Participants and their parent or legal guardian must demonstrate the ability to comply with all trial procedures and be available for the entire follow-up duration. * The infant's parent or legal guardian must have an easily identifiable and stable place of residence within the study area, be available for the duration of trial participation, and have access to a reliable means of telephone contact for communication with the study team. Exclusion Criteria for the first dose: * Infants born at \<35 weeks of gestation. * Infants who have previously received any pneumococcal vaccine. * Infants currently participating in or who have recently participated in another interventional clinical trial. * Infants with an axillary temperature of ≥37.8°C at the time of enrollment (the participant must be deferred until recovery. The visit may be rescheduled when this criterion is met.) * Infants with any congenital abnormalities, chronic medical conditions, or genetic disorders, severe malnutrition, inherited disease and others, that in the investigator's judgment, may interfere with the stud…