COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of April 4, 2026

Summary: Week of 4/4/26

Biobot’s national network shows that all major respiratory viruses—SARS-CoV-2, influenza A & B, and RSV—are declining across the U.S. That’s great news. Influenza B is still running high, especially in the Northeast, but it has finally started going down. RSV also remains elevated, though it appears to be close to its seasonal end.

The Bottom Line: All major respiratory viruses are declining, but flu B and RSV are still circulating at meaningful levels. For high-risk individuals—older adults, young children, and those with underlying health conditions—layered protections still matter: masking in crowded indoor spaces, improving ventilation when possible, and using a rapid test if symptoms start (which are available over the counter at pharmacies).

National Outlook

COVID-19

Nationally, SARS-CoV-2 is decreasing.

Influenza

Nationally, influenza A and B are decreasing.

RSV

Nationally, RSV is decreasing.

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 decreasing in the Midwest.

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

RSV: RSV is decreasing in the Midwest.

The Northeast

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

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

RSV: RSV is decreasing in the Northeast.

The West

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

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

RSV: RSV is holding steady 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 April 4, 2026 (MMWR week 13).