Abstract
Wastewater monitoring, including on aircraft, is a highly efficient method for SARS-CoV-2 surveillance, surpassing traditional passenger testing. Airport wastewater sampling is especially useful for tracking virus spread through travel. This study explored the links between SARS-CoV-2 contents and variants from aircraft to city, assessing the impact of detected variants from international travellers versus the local population. A total of 969 SARS-CoV-2 variants using next-generation sequencing and Freyja software were examined to comprehensively understand the links between the four catchment areas—aircraft, airport, wastewater treatment plants (WWTPs), and the metropolitan area—and compared them to the variants detected in hospitals in Stockholm city. SARS-CoV-2 contents in WWTPs reflected local infection rates, requiring analysis from multiple plants for an accurate city-wide infection assessment. Variants initially found only in the aircraft and the airport didn’t spread widely during the study period. Wastewater monitoring proved to be more effective than clinical testing in the early detection of specific variants, with notable delays observed in the clinical surveillance. Furthermore, a broader range of variants are detected in the wastewater surpassing clinical tests. This underscores the vital role of wastewater-based epidemiology in managing future outbreaks and enhancing global health security.