COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of March 21, 2026

Summary: Week of 3/21/26

Biobot’s national network shows that SARS-CoV-2, influenza A, and influenza B are decreasing nationally, while RSV is increasing, driven by increases in the South and Midwest. This has been one of the longest RSV seasons in recent history, causing some states (like California) to extend the recommendation window for infant monoclonal antibodies into April. While we’re getting closer to the end of the respiratory season, it’s still hanging on.

The Bottom Line: Respiratory virus activity for the major viruses is broadly declining heading into spring, but RSV is a notable exception—it’s increasing across some parts of the country. People at higher risk, including older adults, young children, and those who are immunocompromised, should continue taking precautions such as wearing masks in crowded indoor settings, ensuring good ventilation, and using rapid tests when symptomatic.

National Outlook

COVID-19

Nationally, SARS-CoV-2 is decreasing.

Influenza

Nationally, influenza A and B are decreasing.

RSV

Nationally, RSV is increasing.

Regional Outlook

The South

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

Influenza: Influenza A is decreasing in the South, while influenza B is holding steady.

RSV: RSV is increasing 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 increasing in the Midwest.

The Northeast

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

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

RSV: RSV is decreasing in the Northeast.

The West

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

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

RSV: RSV is decreasing 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 March 21, 2026 (MMWR week 11).