Wastewater-based surveillance of respiratory viruses in a geriatric hospital: a pilot study

ABSTRACT

While wastewater-based surveillance (WBS) has informed our understanding of SARS-CoV-2, influenza and respiratory syncytial virus (RSV) circulation in the community, its use in hospital settings remains limited. We aimed to use WBS to understand the dynamics between SARS-CoV-2, influenza (A/B) and RSV loads in the hospital wastewater and infections among patients in a geriatric hospital in Switzerland.We conducted a prospective WBS study which involved the collection of 24-hour composite samples 7 days/week from the centralised hospital wastewater of the geriatric hospital. We measured SARS-CoV-2, influenza A/B and RSV RNA concentrations using digital RT-PCR. Kendall's rank correlation (τ) and cross-correlation function were used to assess the correlation and lag time between the viral RNA loads and SARS-CoV-2, influenza A/B and RSV infections among hospitalised patients.Between 14 October 2024 and 19 April 2025, we collected 166 wastewater samples. The associations between wastewater loads and infections were significant and positive for SARS-CoV-2 (τ=0.29, 95%CI: 0.19-0.39, p