WENATCHEE — Health officials looking at plans to reopen schools have reduced the projected needed sample size from 10,000 in the Wenatchee Valley to 800 per school district.

The Chelan-Douglas Health District couldn’t accomplish testing 10,000 people, because of the manpower they would need, Health Officer Malcolm Butler said Tuesday. Also, each test runs about $150 to perform, so 10,000 tests would cost about $1.5 million. But health officials only need about 800 per school district to get a good sample size, he said.

“The difficulty is, you know, to get a statistically valid sample,” Butler said. “So that we can feel it’s safe to reopen classrooms.”

Officials, who are a part of the Incident Command Team assisting the health district, first floated the 10,000-test idea, said Wenatchee School District spokeswoman Diana Haglund. It sounds like that estimate has since decreased, Haglund said.

A spokesperson for the Incident Command Team could not be reached for comment.

The testing would be conducted in a different manner than was done at Bridgeport and in other communities, to improve the sampling, Butler said. Epidemiologists, including five from the U.S. Centers for Disease Control and Prevention, are helping design a study that would be more random.

“There are methods where you take a set of families and you sort of randomly select various families within the cohort that you’re interested in and then you invite them all to come in to be tested,” Butler said.

Butler believes the health district will have an easier time testing minority groups this time, because of the school district’s support, he said, and because people trust their school districts.

“And I think most families, be they Hispanic or non-Hispanic, are interested in getting their kids back into classrooms,” Butler said.

It is important to get an accurate sampling of the Hispanic community, though, especially since they have a higher infection rate, he said. The epidemiologists know this and will continue to test until they get enough Hispanic families for the sample to be accurate.

“For example, the study design may say we need 70 Hispanic families,” Butler said. “And we would just keep testing until we got to that and the additional testing would just be icing on the cake.”

The Douglas County Commission discussed COVID-19 testing and contact tracing during its regularly scheduled meeting on Tuesday.

Commissioners Kyle Steinburg and Dan Sutton agreed that while both counties might be experiencing a high number of positives, the actual prevalence of the disease in the community could be much lower.

Steinburg said he didn’t think additional testing would lead to Gov. Jay Inslee allowing the county’s economies or schools to reopen. He was concerned that it was a waste of time and resources.

“The problem is that we believe that we understand,” Steinburg said. “It’s very simple to understand, very simple math and the governor’s office doesn’t get it.”

Sutton said the change is that scientists now agree that a different form of testing may show a different prevalence rate in the community.

“So you don’t keep playing the same game and hoping for a different result,” Sutton said. “You find a different avenue to approach the statistics to take them to the officials that are in charge and say here is my proof and here is my evidence.”

Tony Buhr: 664-7123

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