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Respiratory Virus Risk Reports

Comprehensive Insights for COVID-19, Influenza, and RSV

COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of September 27, 2025

 

Throughout the respiratory season, we analyze wastewater for the presence of respiratory syncytial virus (RSV) and influenza virus (types A and B). Together with COVID-19, these three pathogens are outsized contributors to our seasonal respiratory illness burden. In this data series, we’ll guide you through the wealth of data we’ve gathered from our Biobot Network of national sampling sites, aiming to shed light on emerging trends in respiratory virus activity and community viral load. Our goal is to equip you with information to make informed decisions.

Data Note: Samples are collected from participating locations, and processed by our lab team on a rolling basis. Each point on the figure represents the weekly average concentration, from Sunday – Saturday (corresponding to the MMWR week), aligned to that week’s Saturday.

Contributors
Marisa Donnelly, PhD

Public Health Partnerships Epidemiologist

Previous Risk Reports

Summary: Week of 9/27/25

Biobot’s national wastewater network shows that COVID-19 is continues to decrease in week 39 (through September 27, 2025), and influenza A and B, and RSV are holding steady at very low levels. National hospitalizations for COVID-19 also continue to decrease, currently at 2.2 per 100,000 people in week 38 (through September 20). RSV hospitalizations are holding steady at very low levels, currently 0 per 100,000 people while flu hospitalizations have not been updated on the CDC website since May 3rd.

The Bottom Line: We are in a respiratory virus lull: COVID-19 activity continues to decrease, while flu and RSV haven’t started increasing yet.

National Outlook

COVID-19

National SARS-CoV-2 concentrations are decreasing.

Influenza

National flu A and B concentrations are holding steady at very low levels.

RSV

National RSV concentrations are holding steady at very low levels.

Regional

The South

COVID-19: SARS-CoV-2 concentrations are decreasing in the South.

Influenza: Influenza A and B concentrations are holding steady at very low levels in the South.

RSV: RSV concentrations are holding steady at very low levels in the South.

The Midwest

COVID-19: SARS-CoV-2 concentrations are decreasing in the Midwest.

Influenza: Influenza A and B concentrations are holding steady at very low levels in the Midwest.

RSV: RSV concentrations are holding steady at very low levels in the Midwest.

The Northeast

COVID-19: SARS-CoV-2 concentrations are decreasing in the Northeast.

Influenza: Influenza A and B are holding steady at very low levels in the Northeast.

RSV: RSV concentrations are holding steady at very low levels in the Northeast.

The West

COVID-19: SARS-CoV-2 concentrations are decreasing in the West.

Influenza: Influenza A and B concentrations are holding steady at very low levels in the West.

RSV: RSV concentrations are holding steady at very low levels in the West.

Footnotes: 
We continue to monitor the evolving H5N1 influenza virus situation, and can now test samples specifically for H5 (including H5N1) — see our blog here and please reach out to hello@biobot.io if interested. A quick reminder that Biobot’s influenza A assay described in this report includes the H5N1 influenza subtype, which is an influenza A virus, but does not distinguish between the different subtypes of influenza A (e.g. H5N1 vs H1N1). We will share any important updates as we have them via Bluesky and in the risk reports.

Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through September 27, 2025 (MMWR week 39). Clinical data for RSV, influenza, and COVID-19 are from the Centers for Disease Control and Prevention. Updates to clinical data are through September 20, 2025 (MMWR week 38).