Putting wastewater to use, Penn State researchers track COVID-19 trends

"Over time, we can get what we think is a pretty good trend estimate for what's going on."

  • Anne Danahy/StateImpact Pennsylvania

(State College) — A team of Penn State researchers is using wastewater testing to track the rise and fall of the COVID-19 virus in the State College area. WPSU’s Anne Danahy spoke with Andrew Read, director of the Huck Institutes of the Life Sciences, about the project.

Here’s their conversation (It’s been edited for clarity): 

Anne Danahy 

For your research, you’re doing daily monitoring of the wastewater at Penn State’s University Park campus and in State College for COVID-19. How do you do that testing? And how accurate is it?

Andrew Read 

Yeah, there’s a group of us doing this. We take samples from the wastewater plants, and we do the equivalent of the tests that are done on human samples, on the wastewater looking for fragments of the virus in the wastewater,

Anne Danahy 

How much are you measuring on a given day?

Andrew Read 

Well, so that the units here are tricky because obviously, there’s 10s of thousands of gallons of water moving through these systems. And we are doing our tests on roughly a liter of water. So you know, we scale up in the magnifications, are, you know, immense. And we also don’t know how the numbers of virus relate to the numbers of people who are shedding the virus. So there are a lot of unknowns in the system. So I think our measures are more relative, we can see if things, for example, are going up, we can tell how fast they’re going up, we can tell if they’re double, we can compare, how do the levels look now to what they looked like, you know, a month ago, those sorts of things. So that we can see the relative shapes of what’s going on, and some idea of the rate of rise and the rate of declines and so forth.

Anne Danahy 

Right? So you’ve been doing this since the summer of last year, does it? Do you have a pretty good handle on it now of how accurate it is?

Andrew Read 

Yes, we started in the summer, and then we went to daily sampling at the beginning of August. So we now have a good understanding of the day to day variation, the amount of noise we get because of the assay itself, how much we get because of the quality of the wastewater, and so forth. So we have a good feel now, we think, of what is what we can tell. In any one day we can get strange numbers, blips up and down. Some of that we can understand in terms of, for example, if people are using a lot of bleach in a building to clean it, or paint is going into the system or something. But over time, we can get what we think is a pretty good trend estimate for what’s going on and so forth.

The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif. Stanford University researchers are testing sewage in hopes of tracking the emergence and spread of COVID-19 outbreaks.

Justin Sullivan / Getty Images

The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif. Stanford University researchers are testing sewage in hopes of tracking the emergence and spread of COVID-19 outbreaks.

Anne Danahy 

Do your numbers look pretty accurate compared to what you’re seeing — so your numbers are going up at the same time, the state and local numbers are going up?

Andrew Read 

We are very satisfied there’s good match between the numbers that we see and the numbers that are being reported through the Department of Health reporting system. Yes.

Anne Danahy 

Is it pretty unusual to do a daily sampling?

Andrew Read 

Yeah, so we do think we are one of the most intensely sampled communities in the country. When we look at the other places, they seem to be doing it once a week or once every few days. And we are doing it at three separate locations every day. For us that’s been really important in understanding the variation. And I think that gives us one of the clearest pictures of what’s happening anywhere in the country. You know, we compare this to the human testing. And the interesting thing about the human testing is that that itself bounces around. For example, there’s less testing on a Sunday. And when Penn State did its exit testing, before Thanksgiving, there was thousands of extra tests given so of course, more cases found. But none of that was reflected in the wastewater because of course, the underlying trend didn’t change. And so the testing effort on humans, and then of course, the human behavior seeking tests changes through time depending on all sorts of things. Whereas you can’t escape the wastewater.

Anne Danahy 

So can you talk about what what you are seeing things obviously went up in the cases went up in the fall, and then came back down over the holiday and then back up again. What’s the outlook now?

Andrew Read 

So what’s happened since the beginning of January is we got very steep rises. From very low levels over the Christmas period. There were very steep rises, particularly in the downtown area and State College, that rose very steeply, but so too on campus and in the main borough plant, until somewhere around about the middle of January. And then it turned over in all those sites and went down quite steeply, particularly in the downtown area. So we got a mini wave in the downtown area, which is so far over.

Anne Danahy 

So hopeful that it will stay that way.

Andrew Read 

I’ve got very serious concerns that what’s going to happen is people are going to start feeling relaxed, the sun’s coming, we’re going to get more activities. People are feeling like, well, there’s vaccines around now, we can let our guard down. I don’t think we’re gonna be able to let our guard down actually for quite a few months, because it’ll take some time before the vaccine coverage is high enough to really make a dent on this. My personal prediction is that there’s going to be an increase again soon, the next few weeks, because of that relaxation. It’s typically what we see across the country. You get these big restrictions put on, the numbers go down, people relax, the restrictions are pulled and things go up again. But right now it’s on the downward trend.

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Anne Danahy 

Could this be a comparatively cheap way for other institutions at other Penn State campuses or at prisons I’m thinking to be able to have that other way of measuring what’s going on and whether there is an increase in cases?

Andrew Read 

Yeah, so we’re actually working with a couple of prisons on that. And how useful it is in other places depends a lot on the sort of plumbing they have. If we can, if you can get the samples in the right sort of places, if the catchments capture the right sort of areas. So for example, we have the whole of campus draining into one wastewater plant here. And so that makes it very easy to sample the whole of wastewater, the whole of campus with one one liter sample a day, if your township is broken up. So there’s the catchments are very different. It’s, it can be quite challenging, but it is much cheaper than the human testing, it’s broadly speaking, once you’ve got the hardware to do the sampling in places in place, then the actual testing of the samples is roughly the same cost as human testing. And you test you know, 100,000 people in one test compared to the amount of money that’s spent on human testing. So I think going forward, this is likely to become more and more of the way we do sentinel surveillance. Once we hope the vaccine has had vaccines have had really big impact, and it’s now a much smaller problem, then we’ll be able to tell whether there is a virus on campus or in town, how much whether it’s on the rise when the human testing is no longer as extensive as it is now.

Anne Danahy 

Once there’s widespread vaccination, is it still a good idea do you think to continue to measure for this or possibly for future diseases?

Andrew Read 

I do think it’s going to be important. It’s not like what’s the vaccination is not going to suddenly stop this thing. So it at the moment, it’s hard to imagine the coverage will get much higher than 70%, maybe 80% just given the number of people saying they’ll take the vaccine. That’s more than enough to continue transmission. And so we will, I think, see outbreaks going forward for probably many years. And so this will be a very sensible, easy, cheap way of doing the outbreaks. Keeping an eye on the outbreaks, understanding if you’ve got a local problem before the cases start showing up in hospitals or in clinics. So I do think this has got a lot of prospect going forward for COVID-19. But you’re absolutely right about other diseases and we can we can also look at pharmaceuticals in the water as well. So there’s quite a lot of things that can be done with this once it’s up and running. For example, we could probably look at flu as well. My bet is that you know we had three Coronavirus spillovers this century so far. COVID-19 is not going to be the last one. We could keep an eye out for COVID 24 or COVID 28.

 

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