Observations of respiratory syncytial virus (RSV) nucleic-acids in wastewater solids across the United States in the 2022-2023 season: Relationships with RSV infection positivity and hospitalization rates

Abstract

Respiratory syncytial virus (RSV) is a leading cause of respiratory illness and hospitalization but surveillance detects only a minority of cases. Wastewater surveillance could determine onset and extent of RSV circulation in the absence of sensitive case detection, but to date, studies of RSV in wastewater have been few. We measured RSV genomic RNA concentrations in wastewater solids from 176 US sites that provided samples at least three times per week during the 2022-2023 RSV season. Concentrations ranged from undetectable to 107copies per gram dry weight (median = 103cp/g). Wastewater RSV RNA concentration aggregated at state and national levels correlated with case positivity and hospitalization rates. Onset of RSV season was assessed for 14 states that collected data prior to the start of the RSV season. Wastewater and clinical surveillance identified onset of RSV during the same week in 3 states, whereas in 3 states, wastewater onset preceded clinical onset, and in 7 states, wastewater onset occurred after clinical onset. Wastewater concentrations generally peaked in the same week as hospitalization rates, but after case positivity rates peaked. Differences in onset and peaks in the wastewater versus clinical data may reflect inherent differences in the surveillance approaches.