Making waves: Defining the lead time of wastewater-based epidemiology for COVID-19

• Published in: Water research (Oxford) Vol. 202; p. 117433
• Main Authors: Olesen, Scott W., Imakaev, Maxim, Duvallet, Claire
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2021; The Authors. Published by Elsevier Ltd
• Subjects: COVID-19; COVID-19 infection; disease incidence; disease prevalence; Humans; Lead; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Surveillance; viruses; Wastewater; Wastewater-Based Epidemiological Monitoring; Wastewater-based epidemiology; water; COVID-19; SARS-CoV-2; Surveillance; Wastewater-based epidemiology
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2021.117433

Individuals infected with SARS-CoV-2, the virus that causes COVID-19, may shed the virus in stool before developing symptoms, suggesting that measurements of SARS-CoV-2 concentrations in wastewater could be a “leading indicator” of COVID-19 prevalence. Multiple studies have corroborated the leading indicator concept by showing that the correlation between wastewater measurements and COVID-19 case counts is maximized when case counts are lagged. However, the meaning of “leading indicator” will depend on the specific application of wastewater-based epidemiology, and the correlation analysis is not relevant for all applications. In fact, the quantification of a leading indicator will depend on epidemiological, biological, and health systems factors. Thus, there is no single “lead time” for wastewater-based COVID-19 monitoring. To illustrate this complexity, we enumerate three different applications of wastewater-based epidemiology for COVID-19: a qualitative “early warning” system; an independent, quantitative estimate of disease prevalence; and a quantitative alert of bursts of disease incidence. The leading indicator concept has different definitions and utility in each application.