Wastewater switch

A change is brewing in the public health world about wastewater. And there’s a lot of misinformation circulating.

Here’s what’s going on.

First, setting the playing field.

It’s not an understatement to say that wastewater surveillance has transformed public health. (See my previous post on its pros and cons.) It picked up a SARS-CoV-2 wave before any other metric. We are now using it for flu, RSV, and even opioids. The potential is endless.

Over the past 4 years, the CDC has built a network of wastewater sites—now up to 1,200 sites representing 40% of the U.S. population. (There are over 16,000 wastewater sites in the U.S.; CDC isn’t at all of them.) At each site, a lab processes the samples. Who processes the samples at each site differs:

• 75% of sites: public health laboratories process data

• The other 25% of sites: Biobot—a wastewater startup company—has processed the samples. CDC paid Biobot to do this through a contract.

All of this data is fed back to the CDC. And is displayed on their website.

However, I have consistently used Biobot’s graphs, like the one below, in the YLE newsletter. Their ability to tell a data story is one reason people love them. It’s easy to understand and, thus, act on.

Verily vs. Biobot

This summer, Biobot’s contract was up for renewal. But other companies threw their names in the ring. In September, a big surprise was unveiled: Verily (not Biobot) got the contract.

Verily is an arm of Google’s parent company, Alphabet. They have conducted wastewater testing at ~200 sites* throughout the pandemic and supported Stanford’s WWScan to display data.

The two companies have similarities and differences, but as seen below, both have shown similar trends throughout the pandemic, which we would (hope and) expect, and both collect pools of data (i.e., we’re not giving our individual stool samples to Google). It’s not clear why the CDC made the switch. But word on the street is that Verily can do it for less money because of how they process samples.

Biobot (blue) versus Verily (black) wastewater data. Source here

Okay, why does a switch matter to me?

In theory, it shouldn’t. Switching processors wouldn’t normally create a huge data lag. Verily has the operations in place, they just need to engage with the sites. Probably would take weeks.

But, as you can imagine, this switch is not welcome to Biobot. So in mid-October, they contested this decision through the U.S. Government Accountability Office. Because of this, Verily has a stop work order for 100 days.

It’s hard to understand the implications for you and me in trying to stay up-to-date on Covid-19 today. But this is what I’ve gathered:

Right now, not much changes. For those of us who like using the Biobot site, you can still visit their site to see graphs to understand regional or national transmission. And they have funding to keep up through this respiratory season (beyond this, sustainability is unclear). But keep in mind:

• Biobot has reduced reporting frequency to once per week. To the average person, this doesn’t matter.

• Biobot data is less representative. They have about 2/3 the coverage as before. And, even before, they were a small chunk of the big picture. This matters because we want data that is closest to the “truth” of transmission so you are well-informed of risk in your state or region.

Changing your internet browser bookmark to another source may make sense. Eventually. Going to the CDC site is theoretically better, as they have the most comprehensive data view. And, this Verily stop work order really will only impact 25% of their data. However, it’s nearly impossible to navigate their dashboard. This needs to change quickly (and will soon).

Bottom line

There is a substantial switch happening with wastewater surveillance in the U.S. Will this impact you and me? Not really. But the confusion and switch timing is certainly not ideal, given this is the respiratory season. If any of this changes, I’ll keep you updated.

Love, YLE

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Disclosure: I am a consultant to the CDC, including recently working with the wastewater team to overhaul their dashboard and data story.

*A previous version stated that none of the sites overlapped with CDC. This is incorrect and confusing, so I removed it.

“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH Ph.D.—an epidemiologist, wife, and mom of two little girls. During the day, she is a senior scientific consultant to several organizations, including the CDC. At night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health world so that people will be well-equipped to make evidence-based decisions. This newsletter is free, thanks to the generous support of fellow YLE community members. To support this effort, subscribe below: