The unexpected summer surge: Experts reveal symptoms to watch for as ‘winter virus’ spreads

A stark rise in COVID-19 cases is being reported across all 50 US states, according to the Centers for Disease Control and Prevention.

‘As of August 12, 2026, we estimate that COVID-19 infections are growing or likely growing in 50 states, declining or likely declining in 0 states, and not changing in 0 states,’ the CDC said.

While Covid is typically thought of as a winter virus, along with flu and RSV, experts are seeing infection rates rise despite the warm weather, particularly in southern and western states, with California and Texas among those reporting the highest spike in cases. 

Despite this uptick, the CDC said the weekly percentage of emergency department visits attributed to COVID-19 remains very low, at just 0.3 percent. The agency added that overall respiratory illness levels across the nation also remain low.  

Wastewater data helps fill the gaps in COVID-19 tracking, as fewer people are testing for the infection than they did during the height of the pandemic. The national level of COVID activity in wastewater is ranked as ‘very low,’ per August 8 CDC data.

In contrast, data from WastewaterSCAN, a Stanford University-run infectious disease monitoring program, showed that COVID activity in wastewater is ‘high’ across the US, with an ‘upward trend’ over the past three weeks. 

The dominant variant spreading across the US is XFG.1.1, which accounted for 22 to 40 percent of all COVID-19 cases in July, according to the CDC. The variant is more contagious than previous strains but does not appear to cause more severe illness. 

Still, the weekly rate of positive COVID-19 tests has decreased year-over-year. Last week, about four percent of tests came back positive, compared with more than nine percent at the same time in 2025.

Health experts aren’t too surprised by the increase in cases toward the end of summer, with some noting that a similar trend emerged last August. They believe COVID-19 may have settled into a seasonal pattern..  

‘If you look back over the last few years … the lowest rates across the country are usually late June, early July, and then in August you start to see this increase in rates,’ Dr Susan Kline, professor in the division of infectious diseases and international medicine at the University of Minnesota, told HuffPost.

‘And last year there was actually a peak in late August, going into mid-September. And we don’t know for sure if that’s going to be replicated this year, but it is a possibility.’

Experts also say the current wave of COVID-19 infections appears to be less severe than previous years. 

The CDC recommends the COVID-19 vaccination for everyone six months and older, stressing that staying up to date with vaccinations is a ‘more reliable way to build protection’ against the illness than becoming infected. 

However, recent data showed that since October 2025, the number of people who say they will probably or definitely not get vaccinated has increased.

People with COVID-19 can experience a wide range of symptoms, from mild to severe, which may appear two to 14 days after exposure to the virus. Symptoms can start out mild and progress to more serious illness.

Common symptoms in 2026 include cough, sore throat, congestion, fever, shortness of breath, headache, nausea, vomiting, diarrhea and fatigue. 

While most recover on their own, those at greatest risk of severe illness include adults 65 and older, people with weakened immune systems and those who are unvaccinated.

The infection can be treated with antiviral medications, which can reduce the severity and duration of symptoms when taken early. 

The CDC recommends staying home and away from others until symptoms have improved and you have been fever-free for at least 24 hours without using fever-reducing medication.