![Chart titled, "State Summary of California for SARS-CoV-2 (Last Update: 09/25/2025)." The left side of the chart includes text boxes with summary statistics about SARS-CoV-2 in California wastewater. Text reads: "State aggregated summary: Level: High; Trend (compared to 21 days ago): Decrease -42% [-45%, -39%]
Data Source: All Laboratories. 21 day Trend Summary: Number of sites reporting data in past 21 days: 81; Increasing at 7/81 sites (9%); Decreasing at 70/81 sites (86%); Plateauing at 4/81 sites (5%); Concentrations too low to define trends 0/81 sites (0%)." The right side of the chart is a line graph, titled, "State Aggregated Plot for SARS-CoV-2." The Y axis represents viral levels and the X axis represents time, spanning November 2024 to September 2025. Levels increased consistently from April 2025 through late August, then declined dramatically in September, but remain in the "high" part of the chart.](https://i0.wp.com/thesicktimes.org/wp-content/uploads/2025/09/CDPH-9.25.jpg?resize=1024%2C493&ssl=1)
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 2.3 in every 100,000 people were hospitalized for COVID-19 during the week ending September 13.
- COVID-19 test positivity decreased significantly, from 9.7% of COVID-19 tests returning positive results during the week ending September 13 to 7.8% during the week ending September 20.
- SARS-CoV-2 concentration in wastewater has decreased 20% between the week ending September 13 and the week ending September 20, and the national wastewater viral activity level is “moderate,” per the CDC.
- SARS-CoV-2 concentration in wastewater decreased 25% between September 10 and September 17, and the national wastewater trend is “medium,” per WastewaterSCAN.
COVID-19 levels continue to decline across much of the U.S. as we proceed down the other side of this summer’s wave. But infectious disease spread remains high, especially in parts of the West Coast and South that had the highest peaks this summer; plus, cases might be trending further up in parts of the Northeast and Midwest.
All three major wastewater data sources (the CDC, WastewaterSCAN, and Biobot Analytics) report declines in their national average SARS-CoV-2 levels as of mid-September. Both the CDC and WWSCAN also changed their national trend assessments in their latest updates: the CDC went from “high” to “moderate,” and WWSCAN went from “high” to “medium.”
Test positivity and emergency department visits from the CDC’s reporting networks are also declining nationwide, as they have for a couple of weeks. The CDC’s infectious disease forecasting center estimates that COVID-19 cases are “declining or likely declining” in 36 states as of September 23, and only “likely growing” in one state, Arizona.
However, two notes of caution. First, even multiple weeks from the peak of this wave, disease levels remain high in parts of the West Coast and South where it hit the hardest. In California, for example, the state’s aggregated SARS-CoV-2 wastewater level dropped by 42% between August 28 and September 18 and levels dropped at the vast majority of the state’s 81 testing sites. But the state’s aggregated viral level remained “high” as of September 18, according to the California public health department.
Second, there are signs of disease trends reaching a plateau or perhaps even going back up in parts of the Northeast and Midwest, regions that saw relatively fewer cases over the summer. The CDC’s and WastewaterSCAN’s regional wastewater trends both report a potential slight increase in the Northeast in their most recent data (through mid-September). And the CDC’s regional test positivity data report an increase in health region eight, which includes Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming.
These are all preliminary data, but they are still worth keeping an eye on. I also closely follow wastewater data in New York City — both because I live there and because the city is often a bellwether for new COVID-19 trends — and noticed that some city wastewater testing sites (such as Red Hook, in Brooklyn) reported higher levels in September than they did all summer.
Meanwhile, we still don’t have data yet on how many people are receiving this year’s COVID-19 vaccine. The CDC’s vaccination trends data page says that it will begin sharing updates for the 2025-26 season in “late October,” later than those data started to be available last year.
