Back in May, Allahpundit wrote a story about a study at Yale which found that by testing wastewater in the town of New Haven, researchers could anticipate a rise in the spread of the virus before it became evident in other ways. The University of Arizona has put that research into action as students returned to school. By testing watsewater the school was able to single out two people who were positive for the virus but who didn’t have symptoms and isolate them quickly.
The way it was done was pretty clever. The team tests the wastewater coming out of each dorm and once they find a positive result, they go to that dorm and test everyone there to identify who is shedding the virus.
Wastewater samples from the Likins dorm on the University of Arizona campus came back positive for COVID-19, according to university president, Dr. Robert Robbins.
Dr. Robbins said they tested the water again, and all five samples came back positive.
He said they performed roughly 311 COVID-19 tests on students and staff in the Likins dorm, and found two positive cases.
Dr. Robbins said those individuals are now in isolation, and they are conducting contact tracing. He said wastewater collected from the other dorms showed no traces of COVID-19.
There’s an entertaining thread about this on Twitter, which is where I heard about it. This goes into a bit more detail:
Some big news out of the University of Arizona (@uarizona):
UA scientists & staff found a coronavirus outbreak on campus *before it happened* — and seem to have snuffed it out.
How in the world do you do that?
You use wastewater testing.
— (((Charles Fishman))) (@cfishman) August 27, 2020
3/ As campus reopened, Arizona set up a system to test the wastewater leaving about 20 buildings on campus, including all the dorms that are occupied.
Early work in Europe in the spring showed that people infected with coronavirus shed it into their stool very early.
— (((Charles Fishman))) (@cfishman) August 27, 2020
5/ Those 2 Arizona undergrads are in isolation at UA's isolation dorm now (& their contacts being traced).
The other 309 residents of Likins: Back to covid-life-on-campus.
Mind you, all 311 of those residents had already been tested once, on arrival, and come up negative.
— (((Charles Fishman))) (@cfishman) August 27, 2020
7/ Those two students would have wandered their dorm, asymptomatic, likely infecting their fellow students unknowingly.
Then instead of 2 students in Likins being infected, you might have had 10.
Those students would have been out and about on campus, and in Tucson.
— (((Charles Fishman))) (@cfishman) August 27, 2020
9/ But wastewater testing is a reasonable surrogate.
In Europe, it caught infections a week before anyone showed symptoms.
In practice, at UArizona, that's exactly what happened: A dorm outbreak, detected, isolated, stopped in its tracks.
This is how you do it.
— (((Charles Fishman))) (@cfishman) August 27, 2020
11/ Wastewater testing is not common at all — here in the US, or anywhere else.
It requires a consistent population (you wouldn't want to wastewater test a restaurant or a movie theater), it requires access to the pipes, & an understanding of the plumbing.
— (((Charles Fishman))) (@cfishman) August 27, 2020
13/ Lots of *cities* don't have much in the way of quick-test ability on demand.
But this is how it's done. This is how you find people who might get sick, isolate them, and get back to work.
Imagine using wastewater testing at high schools, for instance, or workplaces.
— (((Charles Fishman))) (@cfishman) August 27, 2020
15/ UArizona's most recent testing data:
Total tests since reopening:
• 10,126 tests
–>46 positiveWednesday, 8/26 testing:
• 770 tests
–> 9 positiveNote that yesterday's results are a small warning.
Overall positive rate: 0.5%
Yesterday's positive rate: 1.2%— (((Charles Fishman))) (@cfishman) August 27, 2020
17/ But UArizona's wastewater testing is a smart, invaluable technique.
Let's hope other colleges and universities, and lots of other organizations, jump in and put it to use as well.
#
— (((Charles Fishman))) (@cfishman) August 27, 2020
It seems like the key to making this work is first that the scale has to be fairly small. It seems like a smart way to deal with possible outbreaks on college campuses where you can isolate individual dorms. Would it work at a high school? You could test the wastewater coming from the entire school but if it’s a school of 3,000 that really doesn’t narrow things down very much.
And it obviously wouldn’t help much to test the water at a waste treatement plant in a city of 100,000 because that doesn’t tell you anything about who has it. You’d really need to do this building by building or at least block by block to make it worthwhile. I can’t imagine how many people you’d need to try this in Los Angeles or San Francisco.
On the plus side, this is actually preventative. It’s certainly not glamorous but if it works maybe that would be enough to make it politically palatable.
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