The United States is experiencing a late summer COVID-19 surge, with coronavirus concentrations in wastewater rising significantly across multiple regions, according to data from the U.S. Centers for Disease Control and Prevention and infectious disease monitoring programs. While national COVID activity remains categorized as low, infections are growing or likely growing in 35 states, driven largely by increases in the South and West.
According to the U.S. Centers for Disease Control and Prevention, COVID-19 activity is increasing quickly in states including California, Nevada, and Texas, which are reporting the highest levels of virus detection in wastewater systems.
Wastewater Tracking Reveals Regional Surges
Data from WastewaterSCAN, a Stanford University-run infectious disease monitoring program, indicate that SARS-CoV-2 activity is high nationwide, showing a significant upward trend over a 21-day window. Amanda Bidwell, WastewaterSCAN Scientific Program Manager, noted that concentrations have maintained a steady increase since late June. By late August, national SARS-CoV-2 concentrations had jumped 140% compared to July figures. In the West and South, current wastewater concentrations have already surpassed the peak levels observed during the 2025–2026 winter wave, according to Bidwell.
Parallel data from the Pandemic Mitigation Collaborative’s data tracker reported that at least 33 states and territories experienced active COVID outbreaks as of September 7. Michael Hoerger, Ph.D., an assistant professor at the Tulane University School of Medicine who leads the PMC, called those spread levels troubling for residents in affected areas.
Seasonal Patterns and School Impacts
In south Texas, the San Perlita ISD was forced to close for several days, shutting down from August 25 to August 26 to protect the health and safety of students and staff amid a rapid local spread of the virus.
Public health experts emphasize that the current wave follows an established post-pandemic rhythm. Dr. William Schaffner, an infectious disease specialist and professor of medicine at Vanderbilt University Medical Center, explained that the SARS-CoV-2 virus spreads year-round but has settled into a distinctive pattern featuring two major waves annually—one in the middle-to-late summer and another during the winter.
“We’ve had two waves (every year). One in the middle to late summer, and the other during the winter,” Schaffner said, noting that while the national data is ticking up, the overall increase remains modest compared to the intense summer surge fueled by the “Stratus” variant in 2025.
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