Wastewater-Based Epidemiology

Wastewater-based epidemiology — the testing of raw sewage for pathogens such as the SARS-CoV-2 virus — provides a non-invasive, cost-effective way to measure community health, including in areas where clinical testing may be underutilized or unavailable. It is a leap forward in extending health equity to people without access to medical care.

Early in the COVID-19 pandemic, the Discovery Partners Institute, University of Illinois Chicago, Northwestern University and Argonne National Laboratory formed a science team to track the coronavirus in wastewater. Working from scratch in 2020, the team chose collection sites, based on social vulnerability, and a workflow for collecting and analyzing samples from treatment plants and sewers in neighborhoods, airports and jails. Implementation involved a unique public-private partnership, including City of Chicago, Cook County, the Metropolitan Water Reclamation District, nonprofit organization Current Water and private contractors, which evolved into a surveillance system adopted by the Chicago Department of Public Health in 2021.

The Illinois Department of Public Health engaged the team, also in 2021, to build the Illinois Wastewater Surveillance System. The collection and transport of statewide samples required a new approach to logistics. A network of wastewater treatment plant operators volunteered to offer samples and a high-throughput lab was developed at UIC to process 150 samples a week, leading to designation as a national Wastewater Center of Excellence. Argonne developed methods to sequence wastewater samples, providing data on COVID-19 variants at a scope, speed and quality not previously seen and yielding Illinois’s first detections of the BA.2 and BA.4 variants. Northwestern headed efforts to enhance and customize data analytics for Illinois public health needs while DPI managed program logistics.

By late 2022, we were collecting samples from over 85 locations, providing reliable, crucial public health information for 9 million Illinoisans at a cost of less than $1 per person each year. To date, over 6,500 samples have been analyzed and close to 5,000 samples have been sequenced. Total funding, largely from the city and state public health departments, comes to more than $17 million and extends the surveillance through mid-2023.