Here are the latest national Covid-19 trends, according to the U.S. Centers for Disease Control and Prevention (CDC) and major wastewater surveillance providers:
- About 0.8 in every 100,000 people was hospitalized for Covid-19 during the week ending May 18. (Note that these are provisional data.)
- Covid-19 test positivity has increased 6%, from 3.2% of Covid-19 tests returning positive results during the week ending May 11 to 3.4% of tests during the week ending May 18.
- Healthcare visits for influenza-like illness have decreased 2% between the week ending May 11 and the week ending May 18, and these visits are below the baseline for respiratory virus season.
- SARS-CoV-2 concentration in wastewater has increased 8% between the week ending May 11 and the week ending May 18, and the national wastewater viral activity level is minimal, per the CDC.
- SARS-CoV-2 concentration in wastewater has increased 17% between May 13 and May 20, per WastewaterSCAN.
Covid-19 metrics show continued signs that we’re at the start of a summer wave in the U.S., with the West Coast reporting more of a pronounced increase in transmission than other regions. Newer variants with the FLiRT mutations are contributing to this increase, but it will be a few more weeks before we understand their full impact.
The major wastewater data providers agree that SARS-CoV-2 spread has been trending up nationally for the last couple of weeks. The CDC’s dashboard reports a more modest increase and still puts coronavirus levels in its “minimal” category, while WastewaterSCAN reports a steeper increase and puts the country in its “medium concentration” category.
Biobot Analytics, which discontinued its Covid-19 wastewater dashboard last week, is still sharing some data via “respiratory virus updates” (even though, as we’ve published, Covid-19 is far more dangerous and deadly than actual respiratory diseases flu and RSV). In its update for the week of May 20, Biobot reported that national coronavirus levels increased slightly, to 250 viral copies per milliliter of wastewater. This is moderately higher than the levels Biobot reported in late May of last year, according to the historical data I’ve saved from the company.
The West Coast is likely driving this recent increase in Covid-19 spread, according to the CDC and WWSCAN’s wastewater data as well as modeling estimates from the CDC’s outbreak forecasting center, which utilizes hospitalization and wastewater data to estimate disease burden. As of May 21, this center estimates that “Covid-19 infections are growing or likely growing in 14 states and territories,” with those states including California, Oregon, Nevada, Arizona, Montana, Wyoming, Texas, Louisiana, Massachusetts, Alaska, and Hawaii.
Covid-19 test positivity continues to trend slowly up, too, according to the CDC and Walgreens’ dashboard. Per the CDC’s variant tracking, new virus strains with the FLiRT mutations (KP.2, KP.3, KP.1.1) are contributing to this increase, as they caused more than half of new cases in the two weeks ending May 25. The increase in infections has been relatively slow so far, potentially suggesting that the newer variants aren’t too much more infectious than the prior dominant strain — but we will need to see how the coming weeks play out to say for sure.
We also continue to keep an eye on the bird flu H5N1. Health officials reported a second human case this week, though a lack of widespread testing among dairy workers likely means other cases have been missed. This week, the CDC asked state and local health departments to keep up their flu surveillance at flu season levels, while the team at WWSCAN has adapted its wastewater surveillance to include H5N1-specific tests. Both measures will help monitor for more widespread human cases.
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