Notes from the Field: The National Wastewater Surveillance System’s Centers of Excellence Contributions to Public Health Action During the Respiratory Virus Season — Four U.S. Jurisdictions, 2022–23

Diana Valencia, MS1; Alexander T. Yu, MD2; Allison Wheeler, MSPH3; Loren Hopkins, PhD4,5; Ian Pray, PhD6,7; Libby Horter, MPH1; Duc J. Vugia, MD2; Shannon Matzinger, PhD3; Lauren Stadler, PhD5; Nathan Kloczko, MPH6; Michael Welton, PhD1; Stephanie Bertsch-Merbach, MA2; Kaavya Domakonda4; Dagmara Antkiewicz, PhD8,9; Hannah Turner, MS1; Chad Crain, MS2; Anthony Mulenga, MS4; Martin Shafer, PhD8,9; Judith Owiti, PhD2; Rebecca Schneider, MStat4; Kayley H. Janssen, PhD8,9; Marlene K. Wolfe, PhD10; Sandra L. McClellan, PhD11; Alexandria B. Boehm, PhD12; Adélaïde Roguet, PhD8,9; Bradley White, PhD13; Melissa K. Schussman, MS11; Madhura S. Rane, PhD2; Jocelyn Hemming, PhD8,9; Caroline Collins, MPH2; Andrew Abram, MPH2; Elisabeth Burnor, MS2; Ryan Westergaard, MD, PhD6; Jessica N. Ricaldi, MD1; John Person, MPH1; Nicole Fehrenbach, MPP1 (View author affiliations)

View suggested citation
Article Metrics

Views equals page views plus PDF downloads

Related Materials
The figure is an illustration of a person coughing with text about wastewater monitoring.

Wastewater surveillance (WWS), the systematic detection of infectious agents in wastewater, provided a valuable tool for monitoring SARS-CoV-2 circulation during the COVID-19 pandemic; surveillance has expanded from 20 to 53 jurisdictions across the United States, with increasing capacity to test for more respiratory pathogens (1,2). This report highlights the use of wastewater data by the four National Wastewater Surveillance System’s (NWSS) Centers of Excellence (California; Colorado; Houston, Texas; and Wisconsin) to guide public health action during the 2022–23 respiratory disease season. This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy.*

Implementation and Action

Four CDC-funded NWSS Centers of Excellence were established during 2021–22. During 2022–23, wastewater sampling covered a large proportion of the sites’ populations: 94% (Houston, Texas), 67% (California), 65% (Colorado), and 50% (Wisconsin). Implementation and data usage varied by locality (Box).

Public Health Actions at the Local Level

Colorado. To help guide local public health action in Colorado, three Denver sewersheds, covering 1.2 million residents, submitted biweekly wastewater samples. Retrospective analyses indicated that WWS detected enterovirus D68 (EV-D68) ≤1 month before syndromic and clinical laboratory signals. This finding led public health officials in Colorado to implement wastewater testing for EV-D68 as part of the enterovirus surveillance model to provide an early warning system for health care surge planning during respiratory virus season.

Houston. This metropolitan area WWS included 122 sampling sites covering 2.17 million residents. Sampling and testing for SARS-CoV-2, influenza virus, and respiratory syncytial virus (RSV) from 48 manholes associated with selected schools provided data to support strategically deployed school vaccination clinics (1,058 COVID-19 and influenza vaccine doses administered), empowered staff members in 48 schools to implement respiratory disease prevention strategies through school reports, and increased public awareness through a dashboard, which recorded approximately 350,000 views as of 2023. Recently, alert notifications were launched (698 registered users are associated with 46 schools) to inform users about identification of surges in respiratory viruses.

Public Health Actions at the State Level

California. In California, WWS supports local health department decision-making, and has been used to provide tailored metrics and messaging to communities, providers, and health care systems to improve awareness and preparedness. Activities included daily to weekly sampling of 98 sewersheds to detect SARS-CoV-2 variants, RSV, and influenza virus in 41 counties, covering approximately 26 million residents; results are communicated via dashboards and weekly reports.

Wisconsin. Wisconsin performed daily to weekly sampling for SARS-CoV-2 at 43 sampling sites covering approximately 2.93 million residents. As of 2023, WWS data were shared on a public dashboard with alert notifications (>250,000 views), a genomic sequencing dashboard (>6,000 views), and weekly reports to local health departments and water treatment utility companies. Wisconsin’s genomic sequencing dashboard has become an important tool for identifying and monitoring SARS-CoV-2 variants in wastewater, in some cases identifying variants (e.g., BA.5 and XBB) before detection through clinical surveillance (e.g., case reports and hospitalizations). Twenty sites covering approximately 2.48 million residents, were sampled for influenza viruses and RSV, and data were monitored on an internal dashboard. Wastewater concentrations for these viruses were highly correlated with emergency department visits in Wisconsin during 2022–23 (3), forming the basis for continued monitoring through the 2023–24 respiratory disease season.

Preliminary Conclusions and Actions

NWSS Centers of Excellence have reported correlation between WWS data and clinical surveillance with WWS allowing localized, timely coverage, and in some situations, valuable lead time notification. In Wisconsin, WWS detected increases in influenza and RSV weeks before increases in related emergency department visits were observed (35). NWSS data, together with clinical surveillance data, have guided jurisdictional partner decisions regarding allocation of resources, deployment of vaccination clinics, updating clinical guidance, and sending respiratory disease notifications and alerts when trends exceed baseline thresholds. NWSS Centers of Excellence have developed public-facing and internal pathogen data dashboards that provide metrics for public health partners and the communities they serve. During the 2022–23 respiratory disease season, NWSS Centers of Excellence translated WWS data into real-time public health action for multiple respiratory pathogens, highlighting the contribution of WWS in monitoring disease circulation and helping guide public health response.


Participating local California wastewater utilities and local health departments; California Association of Sanitation Agencies; Healthy Central Valley Together; Biobot Analytics; partners in the California Department of Public Health (CDPH) COVID control branch, Immunization Branch, and Drinking Water and Radiation Laboratory; SCAN, Verily Life Sciences; CDPH Wastewater Surveillance Team; Erica Pan; participating Colorado wastewater utilities; Laura Bankers, Kevin Berg, Emily Spence Davizon, Nick Pysnack, Kirsten Weisbeck, Colorado Department of Public Health & Environment; Kevin Messacar, Children’s Hospital Colorado and University of Colorado School of Medicine, Department of Pediatrics, Section of Infectious Diseases; Sam Dominguez, Hai Nguyen-Tran, Children’s Hospital Colorado and University of Colorado School of Medicine, Department of Pediatrics, Section of Infectious Diseases; Meghan Birkholz, Molly Butler, Sarah Jung, Children’s Hospital Colorado; Rachel Herlihy; Maria Murillo, Houston Community Liaison team; Kaylan Henderson, Tia Johnson, Martha Stancil, COVID Outreach Team, Houston Health Department; Houston Health Department Sampling Team, Houston Public Works and Sampling Team; Katherine Ensor, Rice University; Rice University and Houston Health Department Laboratory and Analytics Teams; Varun Shetty, Texas Department of State Health Services; wastewater utilities across Wisconsin; University of Wisconsin-Madison; Anna Llewellyn, Cristina Martinez, Dianne Wisham, CDC.

Corresponding author: Diana Valencia,

1Division of Infectious Disease Readiness & Innovation, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 2California Department of Public Health; 3Colorado Department of Public Health & Environment; 4Houston Health Department, Houston, Texas; 5Rice University, Houston, Texas; 6Wisconsin Department of Health Services; 7Career Epidemiology Field Officer Training Program, CDC; 8Wisconsin State Laboratory of Hygiene; 9University of Wisconsin-Madison, Madison, Wisconsin; 10Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia; 11School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin; 12Department of Civil & Environmental Engineering, School of Engineering and Doerr School of Sustainability, Stanford University, Stanford, California; 13Verily Life Sciences, San Francisco, California.

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Martin Shafer reports serving on several Association of Public Health Laboratories’ advisory boards that support wastewater surveillance practice. Sandra L. McClellan reports service on the National Academies of Science, Engineering, and Medicine Community Wastewater-based Infectious Disease Surveillance Committee. Dagmara Antkiewicz reports institutional support from Epidemiology and Laboratory Capacity, Wastewater Surveillance 2020–2021 National Wastewater Surveillance System Budget Period 2, and Wisconsin Alumni Research Foundation COVID-19 Challenge; and uncompensated board membership on the Midwest Society of Environmental Toxicology and Chemistry. Alexandria B. Boehm reports institutional support from Sergey Brin Family Foundation, grants from the U.S. National Science Foundation, public health partnerships with the Sloan Foundation, and membership on the state of California wastewater-based epidemiology committee of the State Water Board. Bradley White reports contract support from Stanford University. Loren Hopkins reports uncompensated leadership of the National Academies for Science, Engineering, and Mathematics’ Committee on Wastewater. Marlene K. Wolfe reports subaward from a gift to Stanford University, grants for implementation of wastewater-based epidemiology in Bangladesh and Ghana from the Rockefeller Foundation, consulting fees from Verily related to the WastewaterSCAN program led by Stanford University, and conference attendance support from the American Society of Microbiology. Lauren Stadler reports support from the Houston Health Department, grants from the National Science Foundation, Jacobs Engineering Group, Dow Chemical Company, U.S. Department of Agriculture’s National Institute of Food and Agriculture, U.S.–Egypt Joint Science and Technology Fund, Colorado State University, and National Academies of Science, Engineering, and Medicine; and consulting fees from the Royal Society of Chemistry and State Analytics, LLC. No other potential conflicts of interest were disclosed.


  1. Kirby AE, Walters MS, Jennings WC, et al. Using wastewater surveillance data to support the COVID-19 response—United States, 2020–2021. MMWR Morb Mortal Wkly Rep 2021;70:1242–4. PMID:34499630
  2. Boehm AB, Wolfe MK, White BJ, Hughes B, Duong D, Bidwell A. More than a tripledemic: influenza A virus, respiratory syncytial virus, SARS-CoV-2, and human metapneumovirus in wastewater during winter 2022–2023. Environ Sci Technol Lett 2023;10:622–7. PMID:37577361
  3. DeJonge PM, Adams C, Pray I, et al. Wastewater surveillance data as a complement to emergency department visit data for tracking incidence of influenza A and respiratory syncytial virus—Wisconsin, August 2022–March 2023. MMWR Morb Mortal Wkly Rep 2023;72:1005–9. PMID:37708080
  4. Li X, Liu H, Gao L, et al. Wastewater-based epidemiology predicts COVID-19-induced weekly new hospital admissions in over 150 USA counties. Nat Commun 2023;14:4548. PMID:37507407
  5. Varkila MRJ, Montez-Rath ME, Salomon JA, et al. Use of wastewater metrics to track COVID-19 in the US. JAMA Netw Open 2023;6:e2325591. PMID:37494040
Return to your place in the textBOX. Examples of implemented public health actions related to respiratory viruses — National Wastewater Surveillance System’s Centers of Excellence, four U.S. jurisdictions, 2022–23

Local level

Colorado (Denver metro)

  • Biweekly sampling for EV-D68 in the Denver metro area to guide and collaborate with health system and pediatric providers during 2022–23 respiratory season
  • Biweekly sampling of three sewersheds in Denver, covering 1.2 million residents
  • Three statewide alerts to guide hospitals and providers about increases in cases to plan surge staffing and resource allocation as a result of the EV-D68 syndromic surveillance alarm
  • Wastewater testing performed retrospectively and showed an increasing trend 1 month before the syndromic surveillance alarm; wastewater testing is now part of the EV-D68 multimodal surveillance model


  • Weekly wastewater monitoring for SARS-CoV-2, influenza, and RSV in K–12 schools to detect outbreaks during 2022–23 school year
  • Weekly sampling of 122 sampling sites (39 wastewater treatment plants, 14 lift stations, and 69 manholes) covering 2.17 million residents
  • Forty-eight manholes sampled from 48 schools serving approximately 34,000 students (1.6% of total National Wastewater Surveillance System sewershed and 18.6% of the city’s school population)
  • Data shared on public dashboard (>362,000 views) and 27 reports to schools
  • Data provided for vaccine clinic deployment that administered 1,058 COVID-19 and influenza vaccine doses to 992 students as of May 2023
State level


  • Daily to weekly sampling of 98 sewersheds to estimate SARS-CoV-2 variants, RSV, and influenza disease activity in 41 counties (67% of residents [26 million persons] within sampled sewersheds) during 2022–23 respiratory disease season
  • Messaging to local public health and the public, including through weekly summary reports and dashboards
  • Local public health messaging to health care providers and the community for awareness and to support recommendations (e.g., vaccines and masking) including through media, press reports, and dashboards


  • Weekly or biweekly monitoring for SARS-CoV-2 and variants at wastewater treatment facilities
    • Forty-three sampling sites covering 2.93 million residents
    • Data shared on public dashboards with alert notification (>250,000 views), genomic sequencing dashboard (>6,000 views), and weekly stakeholder reports
  • Weekly or biweekly monitoring for influenza A and B and RSV at wastewater treatment facilities
    • Twenty sampling sites covering 2.48 million residents
    • Internal monitoring dashboard; public dashboard and weekly stakeholder reports in development

Abbreviations: EV = enterovirus; RSV = respiratory syncytial virus.

Suggested citation for this article: Valencia D, Yu AT, Wheeler A, et al. Notes from the Field: The National Wastewater Surveillance System’s Centers of Excellence Contributions to Public Health Action During the Respiratory Virus Season — Four U.S. Jurisdictions, 2022–23. MMWR Morb Mortal Wkly Rep 2023;72:1309–1312. DOI:

MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.
References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version ( and/or the original MMWR paper copy for printable versions of official text, figures, and tables.

Questions or messages regarding errors in formatting should be addressed to