National COVID-19 trends, April 15

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April 15, 2025

Chart from the CDC. Text at the top reads: "This chart shows national and regional trends of wastewater viral activity levels of SARS-COV-2 (the virus that causes COVID-19)." The chart shows the past year of data, April 2024 to April 2025. National trends are shown with a black line, and regional trends are in different colors: yellow for the Midwest, purple for the South, light blue for the Northeast, teal for the West. All four regions had significant COVID-19 waves in summer 2024 and winter 2024-25; the winter wave led to less disease spread at its peak but was longer, and current disease levels are now higher than they were at this time last year.

Here are the latest national COVID-19 trends, according to the U.S. Centers for Disease Control and Prevention (CDC) and major wastewater surveillance providers:

About 1.7 in every 100,000 people were hospitalized for COVID-19 during the week ending March 29.
COVID-19 test positivity has stayed fairly consistent, with 3.8% of COVID-19 tests returning positive results during the week ending March 29 and 3.6% of tests returning positive results during the week ending April 5.
SARS-CoV-2 concentration in wastewater has decreased 8% between the week ending March 29 and the week ending April 5, and the national wastewater viral activity level is “low,” per the CDC.
SARS-CoV-2 concentration in wastewater has increased 4% between March 26 and April 2, and the national wastewater trend is “medium,” per WastewaterSCAN.
Healthcare visits for influenza-like illness have decreased 15% between the week ending March 29 and the week ending April 5, and are now below the threshold for flu season.

The COVID-19 picture in the U.S. continues to look similar to what we’ve seen over the last few weeks: moderate disease spread, declining very slowly or staying consistent in most places. While there are signals of potential increases for some parts of the Northeast and West Coast, it’s too soon to say if a spring/summer surge is imminent.

Wastewater data from the CDC, WastewaterSCAN, and Biobot Analytics indicate that COVID-19 spread hasn’t changed much at the national level between early March and early April. Similar to last week, WastewaterSCAN continues to report a very slight increase while the CDC and Biobot report slight decreases in the most recent data — likely a product of different testing sites and reporting procedures across the different organizations.

Healthcare system data show a similar picture. National test positivity, from the labs reporting to the CDC, continues to hover between 3.6% and 3.8%. Emergency department visits for COVID-19 have declined slowly over the last month. The CDC’s disease modeling center estimates that COVID-19 cases are “declining or likely declining” in 33 states and “not changing” in 12 states, as of April 8.

The modeling center does estimate COVID-19 cases are increasing in one state: California. Some California wastewater testing sites in the WWSCAN network similarly report increased SARS-CoV-2 levels in recent weeks. WWSCAN also continues to report increases for some sites in the Northeast, and New York City wastewater testing sites have reported increases recently, too.

It’s hard to say yet whether these increases are an early signal of a spring surge or vestiges of our prolonged winter wave this year. We’ll get a better understanding of this trend later in April. Experts are also watching for any signs of new variants; a variant called LP.8.1 is currently dominant in the U.S., according to the CDC, but hasn’t contributed to significant increases in disease spread.

In other disease news: we have officially reached the end of flu season for this spring, as the share of outpatient healthcare visits due to flu-like symptoms dipped below 3% in the most recent data. But measles continues spreading widely: as of April 10, health departments have reported over 700 cases across 24 states, along with cases in Canada and Mexico.