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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.
2/ UArizona is one of the schools that has determined to have some in-person classes, and to welcome students back to campus dorms.

Students started moving into dorms about 2 weeks ago.

Class started — on-line & in-person — Monday.
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.
4/ All dorms had been tested once and come up negative.

On Tuesday, one dorm — Likins Hall — showed coronavirus in the wastewater.

On Wednesday, all 311 residents of Likins were given antigen quick-tests. 2 residents were found to be positive — asymptomatic, but positive.
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.
6/ And the initial test of the dorm's wastewater last week was negative.

So those 2 students caught the virus somewhere between coming back to school and Tuesday.

But imagine what would have happened without the wastewater testing.
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.
8/ Arizona doesn't yet have a follow-up testing regime for its students living on-campus. You had to be negative to move into the dorms, there is talk of testing everyone every 2 weeks — but for now, more testing is voluntary.

(You can get a quick test every day if you want.)
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.
10/ Remember the fruitless mantra of the spring?


It's still true. Testing is how you find infections, testing is how you protect people who might get sick, testing is how you protect everyone who isn't yet infected.
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.
12/ Most important: Wastewater testing requires the ability to do follow-up testing completely & quickly.

They didn't test a few kids living in Likins. They tested them all.

They didn't test them using a method that required a 3-day wait for results. 1-hour antigen test.
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.
14/ Arizona has the scientists on campus to develop and manage its wastewater testing. But this is not arcane science.

And to be clear: UA has 5,000 people living on-campus, but another 25,000 living off-campus.

It could still have an outbreak, and have to go all-online.
15/ UArizona's most recent testing data:

Total tests since reopening:
• 10,126 tests
-->46 positive

Wednesday, 8/26 testing:
• 770 tests
--> 9 positive

Note that yesterday's results are a small warning.

Overall positive rate: 0.5%
Yesterday's positive rate: 1.2%
16/ That dramatic jump in positivity might be a quirk of testing and who walked in yesterday. Might be a sign that as students and staff come back to campus, use the restaurants and the classrooms and see each other on the lawns, some transmission might be happening.
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.

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Keep Current with (((Charles Fishman)))

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