Use of antibody tests Pitkin County purchased still are not FDA approved

Pitkin County has 1,000 COVID-19 antibody tests from a Denver-based company.
Courtesy Pitkin County

After dancing around the question for days, Pitkin County officials finally provided an answer Tuesday as to exactly why they won’t use 1,000 COVID-19 antibody tests they received earlier this month.

When Aytu Bioscience of Englewood first received emergency authorization from the Food and Drug Administration to distribute the tests last month, Pitkin County was one of the first in line to get them.

But what they didn’t know in those “fast-moving, early days” of the virus pandemic here was that while Aytu had received approval to distribute the tests, the company hadn’t been granted authorization for their use, Pitkin County Manager Jon Peacock said Tuesday during a morning meeting of the county Board of Health.

“We had the best information we could at the time,” Peacock said. “But as more information came out, … we thought it best to hold off until we got more clarity from the FDA.”

Pitkin County paid $25,000 for the 1,000 tests, or $25 per test, he said.

The main issue is the accuracy of the test, which checks for the presence of antibodies produced by the body to fight COVID-19. That would indicate whether the person has had the disease, as opposed to another, widely used test that determines if a person is currently sick with the virus.

Dr. Kimberly Levin, Pitkin County’s medical officer and an emergency room doctor at Aspen Valley Hospital, said Tuesday that antibody tests tend to have a high rate of so-called “false positives” that can be between 30% and 40%.

So that means someone who tests positive for the virus and returns to work thinking they no longer have to practice the social distancing techniques stressed over the past six weeks can be dangerous, she said.

“That positive result is really a dangerous result,” Levin said. “It could create a lot of danger in our community.”

The other issue is immunity, said Levin and Dr. Steve Ayers, the county’s coroner and another AVH emergency room physician. Doctors and scientists don’t know enough about what kind of immunity, if any, having COVID-19 provides, which further compromises the information gained from antibody testing, they said.

“Is it a week?” Levin said of immunity. “Is it for life? We have no idea.”

Ayers said the two questions make antibody testing “worthless” at this point.

“It’s why I think it’s not a valuable test,” he said. “Are you immune? Don’t know. Did you actively have (COVID-19)? Unsure.”

Levin put the question of receiving a positive result from an antibody test another way.

“What do you do with that information?” she asked. “There’s no value in guiding the person in their behavior.”

The only possible current use Levin said she could envision was running a batch of the tests on residents for whatever beneficial epidemiological information could be gleaned from the results, but not providing the specific results to residents.

“(That) is the only benefit I can think of,” she said. “It does not have any value in terms of what the result is.”

Current antibody tests get hung up on other coronaviruses, of which there are many including the common flu, Ayers said.

That’s why everyone from county leaders including Peacock and Sheriff Joe DiSalvo to doctors like Levin and Ayers to leaders of the local team responding to the virus outbreak like Public Health Director Karen Koenemann have strongly advocated another kind of widespread community testing.

That procedure — called a PCR test — uses a nasal swab and subsequent lab test to determine if a person is actively sick with COVID-19. It is the basis of a new Pitkin County strategy that began Friday in which everyone in the county with even mild symptoms of the virus will be tested, quarantined then isolated and monitored if they test positive.

In addition, the county has added staff to trace the contacts of everyone who tests positive for COVID-19, then quarantine them, as well.

Since Friday, officials have tested 18 people, though the results are still pending, Koenemann said Tuesday morning.

Public health officials announced Friday that they were pivoting away from the previously announced antibody testing strategy to the PCR testing. At the time, despite numerous questions from The Times about why the antibody tests were not being used, those officials did not expressly provide the reason given Tuesday.

The Aytu antibody tests could be used in the future if the FDA approves it, Peacock said.

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