Association between nasopharyngeal colonization with multiple pneumococcal serotypes and total pneumococcal colonization density in young Peruvian children

•Co-colonization with >1 pneumococcal serotype is common in young children.•Co-colonization is not significantly associated with higher pneumococcal densities.•Distinct pneumococcal serotypes may have varying propensities for co-colonization.•Highly sensitive detection methods may elucidate pneumococcal colonization dynamics. We examined the association of nasopharyngeal (NP) pneumococcal co-colonization (>1 pneumococcal serotype) and pneumococcal density in young Peruvian children enrolled in a prospective cohort study. NP swabs collected monthly from children aged