CDC Wastewater Testing
The CDC just unrolled a new wastewater reporting dashboard. Niall Brennan, senior advisor for Data Strategy to Mandy Cohen, the Centers for Disease Control and Prevention’s director, described its data visualization as “underwhelming to say the least.” So in the past month, with a team called “Poo’s Clues,” the agency redesigned the site to provide better information. As Brennan noted, you can see “national trends in Covid-19 viral activity in wastewater in 1 year, 6 month and 45 day increments.”
National Trend
You can also visualize data at the state and territory level. There are also color-coded maps to show the intensity of virus activity.
Regional Trends
Another, more complicated graphic, shows the proportions of different variants of Covid-19 but is difficult to understand.
Covid Variants
Why Wastewater Levels Matter
Wastewater levels of pathogens are used as an early warning system. You can measure the levels of different viruses including polio, RSV, Covid-19 and mpox. The National Wastewater Surveillance System started in September 2020 to detect the amount of virus shed in people’s stool.
It’s great in that it can detect small levels of virus in a large community before there are outbreaks. This is how polio was identified in New York state.
But water is only tested from a cross-section of communities—officials stopped testing in western Maryland, for example, and we know historically that our levels can be different than those in the Baltimore-Washington area.
It might miss prisons, universities or hospitals that use decentralized treatment; it also excludes rural areas that rely on septic systems.
Controversy
Biobot Analytics has provided a great deal of user-friendly information on SARS-CoV-2 RNA in wastewater since it was selected by the CDC in 2021. In September 2023, it lost the contract and was replaced by Verily (formerly Google Life Sciences). Biobot is once again reporting (more limited) data after it filed a protest.
Criticisms Of The Dashboard
That’s the good news about the new data viz. There is still a ways to go for improvement. As @TactNowInfo commented on X, formerly known as Twitter, we don’t know how current the data is in what is labeled as “Current SARS-CoV-2 Wastewater Viral Activity Level.
“Tact” also noted, “They say 350 sites won’t be reported until they have six weeks of data from September 15, 2023. We are well past 6 weeks, and over 500 sites aren’t showing current data. What’s going on?”
Similarly, Tact questions how long reporting delays are since the graphic “doesn’t show BA.2.86, which the CDC variant proportions estimates to be around 8% to 13%.”
There are two other notable criticisms voiced online. The first is that the CDC has made a significant error in terms of risk communication. They use this blue icon to say that Covid-19 risk is high (above). What color do we usually use to denote risk? Red!
@TogetherWeMask said, “Covid-19 level is RED Change the color. Representation matters in data communication. Dr. Cohen, our lives are dependent on your awareness efforts. Millions are already suffering from #LongCovid. Add Masks + HEPA to CDC’s recommendations. More tools. More protection.”
On the other hand, others criticized the color choices for being difficult for those with color blindness.
Another concern, noted by @amesrobb, is that the visibility of some of the lines is very poor. This was specifically a problem for Vermont, where the almost vertical slope of the rise of infections was nearly hidden.
But one of the biggest problems is that testing people for Covid-19 infections has plummeted, so we need to really know how tightly the wastewater levels correlate with the number of infections. Even reporting of hospitalizations and deaths is inaccurate now. Mike Hoerger has developed a correlation and predictive model at his Pandemic Mitigation Collaborative – Data Tracker site. It looks grim.
What Wastewater Levels Could Tell Us
When used correctly, wastewater can show the source of outbreaks and high-risk hotspots, for example, to improve resource allocation.
Mother Jones produced a nice explainer video:
You could narrow down hotspots to particular areas of town and focus your public health efforts on a specific area (a nursing home or prison, for example), to target with education and vaccination, for example.
Things are not looking very bright for a healthy holiday season, with the rise in Covid-19 cases expected to continue through the holidays with a surge. Cases are high and are increasing dramatically. It’s important to remember that getting Covid-19 is not inevitable—you can reduce your risk by limiting the number of people you engage with at gatherings, masking, and improving the ventilation by opening a window slightly, for example. Even Brennan retweeted Plague Poems: