Rethinking pneumococcal surveillance through indoor air sampling.

BACKGROUND: Pneumococcal surveillance remains challenging due to limited invasive disease surveillance and logistically demanding nasopharyngeal carriage studies, particularly in low- and middle-income countries (LMICs). We evaluated indoor air sampling as a non-invasive approach for monitoring pneumococcal circulation and serotype distribution. METHODS: Monthly indoor air samples were collected over 20 months (January 2022-September 2023) in a Belgian childcare center. Samples were analyzed by qPCR for pneumococcal detection and serotype identification. RESULTS: Pneumococci were detected in all samples. After excluding serotypes with known specificity issues, 15 serotypes/serogroups were identified, with a mean of seven per sample. Commonly detected serotypes largely matched those reported in Belgian carriage studies and invasive disease surveillance. CONCLUSIONS: Indoor air sampling captured signals of community pneumococcal circulation and serotype dynamics. With further validation, it could provide a scalable, affordable surveillance tool to support vaccine policy, monitor vaccine impact, and strengthen respiratory pathogen surveillance, particularly in LMICs.