Flu, RSV, and Norovirus Are in Full Swing, While COVID Looms

January 13, 2025 — Most US states are reporting high or very high flu-like activity, while COVID-19 rates remain lower than this time last year.

The nation isn’t out of the woods yet, though, in terms of seeing another tripledemic or even quad-demic.

So far this year, the CDC estimates that 5.3 million people nationwide have had the flu, and the virus has hospitalized 63,000 people, as well as contributed to 2700 deaths, including 11 children.

Nearly 19% of influenza tests are positive, as are about 13% of tests for respiratory syncytial virus (RSV) and 7% of COVID tests, according to CDC data.

Those flu and RSV rates are similar to what was seen about this time last year, but COVID is trailing, at about half its seasonal rate. Also, COVID hospitalization rates are less than half of what they were at this time last year.

Based on wastewater surveillance data, which can help predict whether viruses are expanding or receding, RSV and COVID may still be on the upswing. The CDC says COVID wastewater activity detections are “high.” And eight US states recently reported “very high” RSV detections: Connecticut, Georgia, Louisiana, Maryland, Massachusetts, New Mexico, Pennsylvania, and South Carolina. Another 14 states logged “high” RSV wastewater levels, CDC data show.

Flu detections in wastewater monitoring nationwide is currently shown as “moderate” by the CDC, which only tracks influenza A — the type that accounts for most flu cases.

Meanwhile, norovirus rates have hit what is at least a 5-year high, with positive tests topping 22%, according to data through the end of December. Seasonal norovirus high positive test rates are typically 15% or lower.

The CDC is expected to release updated virus data early this week that will give the first look at post-holiday impacts.

SOURCES:

CDC: “National Respiratory and Enteric Virus Surveillance System (NREVSS),” “COVID-NET Weekly Rates of COVID-19 Associated Hospitalizations (Week End Date 1/4/2025),” “Wastewater COVID-19 National and Regional Trends,” “RSV Current Wastewater Viral Activity Levels Map.”