Since it began shifting students to in-person instruction last month, the Pullman School District has partnered with Washington State University to monitor the presence of COVID-19 in school wastewater.

Joe Thornton, director of operations for the district, said school personnel deliver wastewater samples from each of the four recently opened elementary schools in the district to the WSU campus for testing twice a week. He said the service has been offered at no cost to the district.

“WSU reached out to us as a way to help facilitate us getting K-12 schools open again,” Thornton said. “They were going to start the process to try to get a better handle on where hot spots are up on campus, so they just extended that opportunity to us as well.”

In addition to wastewater screening, Thornton said the district has implemented a number of other measures to keep the virus at bay, including daily attestations filled out by parents confirming their child is not experiencing symptoms. He said the district also has the ability to conduct surveillance testing using cheek swab samples and results are usually returned within 36 hours.

While a negative test for COVID-19 in a school’s wastewater does not necessarily guarantee there is no presence of the disease within the school population, Thornton said it is a good sign. On the other hand, he said tests showing elevated levels in wastewater would give the district a chance to catch any potential cases early and provide them with a way to target specific sites with more aggressive mitigation measures.

“Right now — knock on wood — all of our results have been negative since we started doing this on Jan. 4,” he said. “But if we ended up getting a hit at the school, we’d know that then we would need to do some more intensive surveillance testing at that site.”

Thornton said district leaders are still deciding how and when to bring middle and high school students back for some amount of in-person instruction but those sites will be included in the wastewater screening program, too.

WSU Spokesman Phil Weiler said serving communities within the state is consistent with the school’s mission as a publicly funded land-grant university.

In July, He said WSU adapted lab space on its Pullman campus to test COVID-19 samples from around the state, creating the One Health Diagnostic Lab. He said when school leaders were discussing testing wastewater for the campus and surrounding communities as well, they were told One Health was up to the task.

In addition to testing local elementary schools, Weiler said the program also monitors wastewater in each of its nine occupied residence halls and so far the presence of the disease has been negligible.

“I think that it does provide a level of security in the sense that we know that we’re going to have a good sense of whether there is illness in that population,” Weiler said. “So far, we haven’t seen elevated numbers for any of the schools, which is great. It means that they’re able to make that transition back into in-person in a safe manner.”

Scott Jackson can be reached at (208) 883-4636, or by email to sjackson@dnews.com.

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