We can test for COVID, flu and other respiratory infections at home now — but many of those results never leave our kitchens. So when someone says an infection is rising, how do we actually know? In this solo episode, Dr. Keisha Davis breaks down how disease surveillance works today, from home and clinical testing to laboratories, emergency-department data, hospitalizations and wastewater monitoring.
Using her own recent at-home COVID test as a starting point, Dr. Keisha explains why traditional case counts no longer tell the whole story, why wastewater has become an important public-health signal, and why two dashboards can appear to tell different stories without either one necessarily being wrong. She also looks at CDC's National Wastewater Surveillance System (NWSS), WastewaterSCAN, and what these tools can — and cannot — tell you about what is circulating in your community.
In This Episode
- Why an at-home positive test may never become part of a traditional case count
- Why MakeMyTestCount no longer accepts at-home COVID, flu, RSV or combination-test results
- Why tracking outbreaks matters even when most infections are not severe
- How home testing, clinical laboratories, emergency departments, hospitalizations and death data provide different surveillance signals
- How wastewater can detect community transmission even when people do not seek medical care or testing
- How CDC's National Wastewater Surveillance System (NWSS) works and where its data come from
- Why Dr. Keisha also recommends WastewaterSCAN as a consumer-friendly way to explore local trends
- Why "high" wastewater activity is not the same thing as a COVID case count
- Why wastewater, ER visits, laboratory positivity and hospitalizations can move differently without contradicting one another
- How to use wastewater information as community context — not as an individual diagnosis
Key Facts
- CDC currently receives data from more than 1,000 wastewater monitoring sites across the United States each week.
- WastewaterSCAN reports sampling at nearly 150 locations across 40 states, serving more than 39 million people.
- CDC receives WastewaterSCAN data as one of the data sources used in its national wastewater monitoring program.
- CDC wastewater dashboards currently include influenza A, COVID-19, RSV, measles, avian influenza A(H5), and mpox.
- CDC's National Syndromic Surveillance Program receives near-real-time data from about 85% of U.S. emergency departments, often within 24 hours of a visit.
- Wastewater activity levels are community-level surveillance measures; CDC cautions that they should not be used to estimate the exact number of infections in a community or diagnose an individual.
Key Takeaway
No single number tells us how much disease is circulating. Wastewater, laboratory testing, emergency-department activity, hospitalizations and other public-health signals answer different questions. Like a pathology diagnosis, the clearest picture comes from putting multiple pieces of information together.
Resources & References
WastewaterSCAN — Public Wastewater Dashboard
https://data.wastewaterscan.org/
CDC — National Wastewater Surveillance System (NWSS)
https://www.cdc.gov/wastewater/
CDC — About Wastewater Data
https://www.cdc.gov/wastewater/about-data/index.html
FDA — At-Home OTC COVID-19 Diagnostic Tests and Expiration Dates
MakeMyTestCount — Program Closure Information
https://www.makemytestcount.org/
Recommended Episode
If you want to go deeper into why surveillance and public-health infrastructure matter, listen to:
When Healthcare Becomes a National Security Issue — Are We Prepared for the Next Health Emergency?
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Dr. Keisha Davis, M.D. — Host
Pathology / Laboratory Medicine
Komi: Dr. Keisha Davis
Diverse Doctors. One Mission.
