COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of February 28, 2026

Summary: Week of 2/28/26

Influenza B and RSV are still rising across the U.S., as measured by Biobot’s wastewater monitoring network. Clinical data tell a similar story: the share of positive flu tests caused by flu B continues to grow. Meanwhile, COVID-19 is fluctuating—some regions are increasing while others are declining.

The Bottom Line: The respiratory season is hanging on. Flu B and RSV are still increasing, both of which can cause significant illness, especially for older people, those who are immunocompromised, young infants, and those who are pregnant. While the season lingers, it’s still a good time to layer protections (like masking in indoor crowded spaces or increasing ventilation), and test early if symptoms start (there are now rapid tests for the flu you can buy at your local pharmacy).

National Outlook

COVID-19

Nationally, SARS-CoV-2 is fluctuating—it increased slightly, but is generally going down.

Influenza

Nationally, influenza A is decreasing while influenza B continues to increase.

RSV

Nationally, RSV is increasing again.

Regional Outlook

The South

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

Influenza: Influenza A and B are decreasing in the South.

RSV: RSV is decreasing in the South.

The Midwest

COVID-19: SARS-CoV-2 is increasing in the Midwest.

Influenza: Influenza A is decreasing in the Midwest, while influenza B is increasing.

RSV: RSV is increasing in the Midwest.

The Northeast

COVID-19: SARS-CoV-2 is slightly increasing in the Northeast.

Influenza: Influenza A is decreasing in the Northeast, while influenza B is increasing.

RSV: RSV is increasing in the Northeast.

The West

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

Influenza: Influenza A is decreasing in the West, while influenza B is increasing.

RSV: RSV is increasing in the West.

Footnotes:

We continue to monitor the evolving H5N1 influenza virus situation, and can now test samples specifically for H5 (including H5N1) — 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. 

Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through February 28, 2026 (MMWR week 8).