Dynamic Change and Immune Response to Nasopharyngeal Carriage and Acute Otitis Media Pathogens

Inclusion Criteria: * Male or female subject age 6 to 12 months + 30 days at the time of enrollment when healthy or up to 36 months old + 30 days with an ear infection. * Subject has received full (3 dose) infant series of PCV. * Parent/legal guardian must be able and willing to bring subject to all study visits Exclusion Criteria: * Any major illness/condition that, in the investigator's judgment, will substantially increase the risk associated with the subject's participation in the study. * Participation in another investigational or interventional trial within the 28-day period before enrollment and during the conduct of the study. Participation in observational studies is permitted.