COVID-19, Influenza, and RSV Wastewater Monitoring in the U.S. | Week of December 20, 2025

Summary: Week of 12/20/25

Biobot’s national wastewater network shows that the big three respiratory viruses—COVID-19, influenza, and RSV—continued to rise through the week ending December 20 (week 51). CDC clinical data show the same: hospitalizations for flu and RSV continue to increase, with the sharpest rise seen in flu. COVID-19 hospitalizations are still relatively flat, but we expected them to increase soon following increases observed in wastewater and increased travel from the holidays.

The Bottom Line: Flu is surging right now. Following increased travel from the holidays, we expect all three major respiratory viruses to pick up. It’s still not too late to get vaccinated. We have months of elevated viral activity ahead, and vaccination remains one of the best tools to reduce the risk of severe illness.

National Outlook

COVID-19

National SARS-CoV-2 concentrations are increasing.

Influenza

National influenza A & B concentrations are increasing.

RSV

National RSV concentrations are increasing.

Regional Outlook

The South

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

Influenza: Influenza A & B concentrations are increasing in the South.

RSV: RSV concentrations are increasing in the South.

The Midwest

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

Influenza: Influenza A & B concentrations are increasing in the Midwest.

RSV: RSV concentrations are increasing in the Midwest.

The Northeast

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

Influenza: Influenza A & B concentrations are increasing in the Northeast.

RSV: RSV concentrations are increasing in the Northeast.

The West

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

Influenza: Influenza A & B concentrations are increasing in the West.

RSV: RSV concentrations are 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) — 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.

Wastewater data from Biobot Analytics for RSV, influenza, and SARS-CoV-2 are through December 20, 2025 (MMWR week 51). Clinical data for RSV, influenza, and COVID-19 from the Centers for Disease Control and Prevention are through December 13, 2025 (MMWR week 50).