PneumoTrans will collect nasopharyngeal swabs from participants in Nairobi, Siaya and Kilifi to determine the carriage prevalence of vaccine-type (VT) pneumococci six-eight years after the introduction of the PCV10 vaccine. The study will also identify which age groups are responsible for the residual carriage of VT pneumococci; and investigate how pneumococci are acquired, how long they stay in the body, and how long they take to clear after vaccination. We will use this data to inform mathematic models to identify potential interventions to eliminate carriage of VT pneumococci.