Vigilancia de virus respiratorios en aguas residuales de un hospital geriátrico: un estudio piloto

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<0.01), influenza A (τ=0.36, 95%CI: 0.25-0.44, p<0.01) and RSV (τ= 0.48, 95%CI: 0.38-0.57, p<0.01). In sensitivity analyses restricted to healthcare-associated infections, the associations between wastewater loads and infections among patients remained significant and positive for SARS-CoV-2 (τ=0.32, 95%CI: 0.23-0.41, p<0.01), influenza A (τ=0.24, 95%CI: 0.12-0.34, p<0.01) and RSV (τ= 0.37, 95%CI: 0.27-0.47, p<0.01). Increases in wastewater viral load preceded increases in reported SARS-CoV-2 and influenza A healthcare-associated infections by approximately three and five days, respectively.

WBS could be used as a complementary early warning system for the circulation of respiratory viruses in hospital settings.