COVID-19 is making another late-summer climb across the United States, arriving before the country has even entered its traditional fall and winter respiratory virus season.
The clearest sign is not a return to crowded hospitals or pandemic-era case counts. Instead, it is showing up across several surveillance systems that now track the virus in a country where routine COVID reporting is far less comprehensive than it once was.
By August 19, the US Centers for Disease Control and Prevention estimated that infections were growing or likely growing in 47 states. Earlier CDC modeling had already shown transmission increasing across virtually the entire country, a sharp change from July when several states were still showing little change.
Yet one of the most striking numbers comes from wastewater.
WastewaterSCAN, a Stanford University-based monitoring program, reported that SARS-CoV-2 concentrations in August were 106% higher than in July 2026, following a steady national increase since late June. The same program characterized nationwide wastewater activity as “high.” At roughly the same time, the CDC described national wastewater activity as “very low.”
That apparent contradiction is an important part of the 2026 COVID story. The two surveillance systems use different methodologies and reporting timelines, meaning their labels are not directly interchangeable. CNN also noted that WastewaterSCAN’s data were more up to date, while CDC figures showed an upward trend in emergency-room visits in the West and South.
So, is COVID back?
It never completely went away. What appears to be happening now is another late-summer wave, a pattern infectious-disease specialists say has become increasingly familiar.
A nationwide rise, but not a pandemic-era surge
The geographical spread is broad.
The South and West have been leading the latest increase, with California and Texas among the states showing some of the sharpest upticks. At least 15 states and territories were experiencing active outbreaks by August 17, according to the Pandemic Mitigation Collaborative data cited by TODAY.
CDC epidemic modeling also painted an unusually uniform national picture. Large states including California, Texas, Florida, New York, Pennsylvania, Illinois and Georgia were among those showing infection growth, while many states had a greater than 99% estimated probability that infections were increasing.
But widespread transmission does not automatically mean widespread severe illness.
CNN reported that overall case numbers were not especially high and that the US was not recording large numbers of COVID-related hospitalizations or deaths. Test positivity for the week ending August 8 had moved above 3% for the first time since March.
A few days later, nearly 5% of tests were positive during the week ending August 13. For comparison, positivity exceeded 9% at the same point in 2025.
That distinction matters. The virus is spreading widely, but the available evidence does not show a return to the scale of severe disease seen during the pandemic’s worst periods.
Peter Chin-Hong, an infectious-disease expert and professor of medicine at the University of California, San Francisco, described the situation as a “broad national wave” while stressing that such a wave does not necessarily translate into large numbers of severely ill patients. He advised people to remain aware rather than alarmed, particularly because older adults, pregnant people, people who are severely immunocompromised and very young children can still face greater risks.
Why COVID is rising before flu season?
COVID has increasingly developed its own seasonal rhythm in the United States.
Unlike flu and RSV, which typically peak once during the colder months, COVID has been producing both winter and summer waves.
Dr. William Schaffner, an infectious-disease specialist and professor at Vanderbilt University Medical Center, said the US has generally experienced two COVID waves each year, one in mid-to-late summer and another during winter.
Dr. Caitlin Rivers of the Johns Hopkins Center for Health and Security similarly described August as firmly part of the country’s COVID season, with the South and West again emerging at the leading edge of transmission.
Summer travel and the beginning of a new school year may provide additional opportunities for transmission. Declining immunity following earlier infection or vaccination is another factor experts are watching.
One projection cited by TODAY suggested transmission could peak around the first week of September, although experts cautioned that it remained too early to know exactly how large the wave would become.
No radically different variant is driving the wave
The current increase does not appear to be the result of a dramatically different new variant.
XFG.1.1 was estimated to account for roughly 22% to 40% of US cases in the latest CDC data cited by TODAY. Another strain, BA.3.2, also known as Cicada, accounted for about 15%.
Yale epidemiologist Dr. Albert Ko said XFG remains within the broader family of recent Omicron variants and is not a major evolutionary jump. Experts cited in the reports also said Cicada had not taken off in the US to the extent it had in some other places.
Andrew Pekosz, a professor at the Johns Hopkins Bloomberg School of Public Health, characterized the rise as relatively steady rather than dramatic and said there were no variants or mutations in the US at the time that he considered particularly concerning.
That does not make COVID harmless. It does suggest that the late-summer increase looks more like a recurring seasonal wave than a sudden change in the virus itself.
What symptoms are showing up in 2026?
The symptoms associated with the variants circulating this summer remain broadly similar to those seen with other Omicron strains.
Common symptoms listed by the CDC include cough, sore throat, congestion, fatigue, fever, chills, shortness of breath, headache, nausea, vomiting and diarrhea. Because COVID symptoms can closely resemble those of other respiratory infections, testing remains useful.
The CDC guidance cited by TODAY recommends repeating a rapid antigen test after 48 hours if the first test is negative but COVID is still suspected.
What should you do if you test positive?
Current guidance is different from the fixed isolation periods many people remember from the pandemic.
People who become sick are advised to stay home and avoid others while they are unwell. Normal activities can generally resume once symptoms are improving and a person has been fever-free without fever-reducing medication for at least 24 hours.
Experts also recommend taking extra precautions around people at higher risk of severe illness. A well-fitting N95 or KN95 can provide additional protection while someone is recovering.
The updated 2026-27 COVID vaccines were not yet available when the reports were published, with experts expecting their release during September. The updated formulation is expected to target the XFG variant.
The bigger picture
The late-August numbers point to a real and geographically broad increase in COVID transmission, but they do not point to a return to the emergency conditions that defined the early pandemic.
The most unusual feature of this summer wave may instead be how difficult it has become to measure.
Daily case counts are no longer available in the way they once were. Laboratories do not have to report negative tests, and hospitals no longer provide some of the detailed capacity information collected during the pandemic. The CDC increasingly relies on wastewater surveillance, emergency-room visits and laboratory data to judge where the virus is heading.
That means no single number tells the whole story.
Wastewater is climbing. Test positivity is rising. Infection-growth models show transmission increasing across most of the country. At the same time, hospitalizations, deaths and overall disease activity remain well below the levels associated with previous major waves.
For now, the evidence points to a familiar late-summer COVID wave spreading widely across America, not a return to the pandemic’s darkest phase.
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