COVID Wastewater Data Shows Modest Summer Rise in Select U.S. Regions
CDC wastewater testing indicates a modest increase in COVID-19 activity this summer in several southern and western states, while overall case levels remain low nationwide.
COVID-19 activity is showing a modest uptick this summer in parts of the United States, according to recent CDC wastewater surveillance. The data highlight low but rising levels of the virus in California, Nevada, Hawaii, Florida, Louisiana and Mississippi, with Missouri and Alaska reporting moderate activity.
"I was looking at the CDC data ... and it does look like they’re starting to see an uptick in COVID that they’re finding in wastewater testing in several states, primarily in the South and the West Coast," said Dr. Susan Kline, professor of infectious diseases at the University of Minnesota.
Experts note that wastewater testing has become a useful tool for tracking community trends without requiring individual lab tests. Dr. Kline added that the method offers a convenient way to monitor COVID spread.
Overall case numbers remain low, mirroring the seasonal patterns of other respiratory viruses. Dr. Neil Maniar of Northeastern University said the summer rise aligns with historical trends, where rates typically increase after late June and may peak in late August.
"I don’t think it’s anything to be particularly concerned about in terms of are we going to see another massive surge, but I think it is important for folks to recognize that, as has been the case from the very beginning of this pandemic, there are some very effective ways that we have to keep ourselves safe," Maniar said.
Public health officials continue to recommend basic preventive measures such as hand-washing, mask use in crowded settings, and staying home when ill. They also advise testing if symptoms appear and seeking antiviral treatment like Paxlovid for eligible high-risk patients.
Vaccination remains the primary defense. The current 2025-2026 COVID-19 vaccine is available, while a updated 2026-2027 formulation is expected later in the year. Experts suggest most people wait for the newer shot, though high-risk individuals may consider receiving the existing vaccine now.
"The goal of the vaccine from the beginning has been to reduce the likelihood of hospitalization and death from COVID, and that’s still the case," Maniar said.
The same experts warned of rising measles cases and urged vaccination ahead of the upcoming flu season, emphasizing that existing vaccines are safe and effective tools to prevent large outbreaks.