Levels of COVID in wastewater across the country are up 106 percent this month compared to July, according to WastewaterSCAN, the Stanford-run infectious disease monitoring program that tracks the virus by testing sewage.
If that method sounds strange, it is actually the main way COVID gets tracked now. Nobody is counting daily cases the way they did in 2020 and 2021, and most people who test at home never report the result to anyone. So researchers test the wastewater flowing out of communities instead. The virus shows up in sewage before people start showing up at doctors’ offices, and it registers infections in people who feel completely fine and never test at all. Amanda Bidwell, who manages the WastewaterSCAN program, told TODAY the increase has been steady since late June.
The federal numbers point the same direction. The Centers for Disease Control and Prevention runs a model that estimates whether infections in each state are rising or falling, and as of August 12 it showed COVID growing or likely growing in all 50 states. Not one state was declining. Test positivity, meaning the share of COVID tests that come back positive, crossed 3 percent for the week ending August 8, the first time it had done that since March, and ran closer to 4 percent the following week.
Here is the part worth understanding before anyone panics. That same week last year, positivity was above 9 percent. Hospitalizations and deaths are not climbing the way infections are, and the CDC lists emergency room visits related to COVID as very low. What is happening is a real increase in how many people are catching it, not a crisis in how sick people are getting. There is also a genuine disagreement between the two trackers, and it is worth explaining because you will see both numbers quoted this week. The CDC’s own wastewater report described national activity as very low as of August 8.
WastewaterSCAN, looking at COVID in wastewater over the same period, called activity high nationwide with a clear upward trend over the past 21 days in every region except the Midwest, where it is medium. They use different methods, and the CDC’s data runs further behind, so the Stanford numbers are picking up movement the federal report has not caught up to yet. When two trackers disagree like this, the direction they agree on matters more than the label either one puts on it, and both of them show the line going up.
Geography is uneven. The West and the South are carrying the highest concentrations right now, with California and Texas seeing some of the sharpest increases. As for what is actually spreading, this wave is being driven by a mix of variants people have already seen. A variant is just a version of the virus that has picked up enough changes to behave a little differently. About 15 percent of current cases trace to one called BA.3.2, nicknamed Cicada, which is heavily mutated and spread quickly around the world earlier this year but has not really taken hold in the United States. There has been no dramatic new mutation driving this. Researchers are careful to point out that the absence of a scary new variant does not mean the virus cannot still make people seriously ill, particularly older adults and people with weakened immune systems.
Timing is the reason this is landing in the news now. Transmission is expected to peak about a week into September. That lines up with the end of summer travel and with millions of kids heading back into classrooms, which historically gives the virus a lot of new room to move. Immunity from earlier vaccinations and earlier infections has also been fading for a lot of people.
The symptoms look like every other omicron-era wave, which is to say they look like a summer cold. They generally show up somewhere between two and 14 days after exposure and overlap heavily with what flu and other respiratory viruses do.
There is no way to tell the difference by feel. If you are coughing, run down, or feverish over the next few weeks, a test is the only thing that will actually answer the question, and knowing matters most if you are around anyone elderly, pregnant, or immunocompromised.
