About SCAN

In early 2020, scientists from Stanford University, the University of Michigan, and Emory University developed a method to find the COVID-19 virus (SARS-CoV-2) in sewage and to determine what it indicates about the level of infection in a community.

In November 2020, they partnered with wastewater treatment plants in 10 California communities and the life sciences research company Verily to sample and analyze wastewater solids. The Sewer Coronavirus Alert Network (SCAN) has been sampling, testing, and reporting results from those plants ever since.

The analytical methods and public reporting developed by SCAN are now being scaled nationally through WastewaterSCAN. SCAN’s co-investigators Alexandria Boehm and Marlene Wolfe are the scientific leaders of WastewaterSCAN.

Alexandria Boehm, PhD

Dr. Boehm is a professor of civil and environmental engineering and a senior fellow at Woods Institute for the Environment at Stanford. Her research focuses on pathogens in the environment including their sources, fate, and transport in natural and engineered systems.

She has been working on wastewater based epidemiology since the start of the COVID-19 pandemic. She also studies how pathogens are transmitted to humans through contact with water, feces, and contaminated surfaces. Dr. Boehm’s work addresses key problems in both developed and developing countries with the overarching goal of designing and testing novel interventions and technologies for reducing the burden of disease.

Marlene Wolfe, PhD

Dr. Wolfe is an assistant professor of environmental health at Emory. As an environmental microbiologist, engineer, and epidemiologist, her work focuses on developing tools to use environmental detection of pathogens to understand population health and risks, and to implement and evaluate interventions that reduce environmental exposure to pathogens.

Dr. Wolfe uses mixed methods approaches to understand the efficacy of interventions in the laboratory and how they are utilized and effective in context. Her work particularly addresses communities that are low-resource or facing emergencies to create sustainable and adaptable solutions to understand and manage their relationship to infectious disease.


Since late 2020, SCAN has tested wastewater from 10 communities for SARS-CoV-2, the virus that causes COVID-19. Over time, SCAN has added monitoring for COVID-19 variants and other pathogens including influenza A and B, mpox, and respiratory syncytial virus (RSV) using the same samples.



The researchers leading WastewaterSCAN have added to the field of wastewater-based epidemiology through published papers and open-source protocols available online. An abridged list of articles and protocols appears below.

PLOS Water

Identifying trends in SARS-CoV-2 RNA in wastewater to infer changing COVID-19 incidence: Effect of sampling frequency

Apr 2023

The Lancet Microbe

Wastewater concentrations of human influenza, metapneumovirus, parainfluenza, respiratory syncytial virus, rhinovirus, and seasonal coronavirus nucleic-acids during the COVID-19 pandemic: a surveillance study

Mar 2023

The New England Journal of Medicine

Use of Wastewater for Mpox Outbreak Surveillance in California

Jan 2023

Environmental Science & Technology Letters

Wastewater-Based Detection of Two Influenza Outbreaks

Jul 2022

Environmental Health Perspectives

Wastewater-Based Estimation Of The Effective Reproductive Number Of SARS-Cov-2

May 2022

Emerging Infectious Diseases

Estimating Relative Abundance Of 2 SARS-Cov-2 Variants Through Wastewater Surveillance At 2 Large Metropolitan Sites, United States

May 2022
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