Pneumococcal Carriage Duration

Inclusion Criteria: * Are older than 28 days and under 4 years of age at the time of enrollment. * Have a parent or legal guardian who: 1. Provides written informed consent. 2. Is able to read and speak English or Spanish. 3. Agrees to comply with all study procedures, including completion of questionnaires and biweekly oropharyngeal (OP) swab collections from the child for a period of 12 months. Exclusion Criteria: * History of chronic medical conditions or immunocompromising conditions that may influence pneumococcal carriage or study participation, such as: * cystic fibrosis * cerebral palsy * neuromuscular disorders * congenital heart disease * known congenital or acquired immunodeficiencies * sickle cell disease * undergoing immunosuppressive therapy (e.g., systemic corticosteroids ≥2 mg/kg/day for ≥14 days, chemotherapy, biologics)