Antibody Tests Have Taken Center Stage, But The Nasal Swab Is Key For Idaho's Next Act
Janie Leigh of Nampa was feeling really sick last month. She had a dry cough and a fever. Her whole body ached, even her hair, she said. The illness lasted about two and a half weeks.
Leigh thought she might have coronavirus. But it was early in March, before Idaho had confirmed its first case, and she couldn’t find a place to get tested.
“We reserved PCR testing for people that were super sick or in the hospital, so that’s the mess we’re in," said Tommy Ahlquist, a former emergency room doctor and Treasure Valley developer, talking about the basic nasal swab test that tells whether someone has the coronavirus.
Earlier this month, Ahlquist and a group of Idaho business leaders formed an organization called Crush the Curve Idaho. It aims to gather more data through testing to help state officials who make decisions on how to get Idahoans back to work.
“In two weeks, our little group has been able to secure thousands of tests for both COVID-19 and antibody testing in the state," Ahlquist said.
Antibody tests look for antibodies in a person’s blood that develop in response to infections like the coronavirus. Many people are like Leigh — sitting at home or still working, wondering if that illness they had a few weeks ago might’ve been the coronavirus, and antibody tests seem like an antidote to that burning curiosity. But with their proliferation has also come scrutiny.
“We don't even really understand it yet, how accurate it is, what a positive test means," said Dr. David Pate, the former CEO of St. Luke’s Health System and a member of the governor’s coronavirus task force. He was speaking on Idaho Matters.
Antibody tests have flooded the market in the past few weeks and many of them haven’t been reviewed by the Food and Drug Administration. Only eight of these tests have been authorized for emergency use by the FDA; the Abbott Laboratories antibody test Crush the Curve is using through the University of Washington received its authorization on Sunday.
Policy officials are saying the antibody testing scene is like the “Wild West,” and the U.S. House Oversight Committee is raising concerns about the haphazard FDA approval process for these tests.
The Results — And What They Mean
Last week, Leigh went to a Meridian testing center the first day Crush the Curve offered antibody testing.
"I was interested to know if I had it for sure or not," she said. The whole thing, including the blood draw, took under an hour.
Two days later, Leigh checked her results online and saw the word “negative” pop up.
“I’m pretty devastated about that," she said. It said she hadn’t developed antibodies to COVID-19, meaning she most likely never had the virus.
Even for people who do have antibodies, though, doctors say it doesn’t mean they’re in the clear to work or to stop social distancing. That’s because it’s not yet clear whether having antibodies for coronavirus gives someone protective immunity.
Click here for more on what antibody testing can — and cannot — tell us.
Crush the Curve has said antibody testing will help get Idahoans back to work, and now it’s focusing on the data that’s collected through these tests.
“It is super helpful for policy makers, for people deciding when and how to go back to work, to say how much disease is out there and where are we on the curve," Ahlquist said.
In its first 48 hours of offering antibody tests in the Treasure Valley, Crush the Curve tested 1,946 people. Just 34 — or 1.75% — of them had COVID-19 antibodies. But it wasn’t a scientific sample, the organization's leaders said.
“What you get when you do something like you set up a center where people can come and get tested, is you get a biased sample," said Benjamin Ridenhour, a University of Idaho mathematics professor who is modeling coronavirus cases for the state.
He said people who showed up likely thought they might’ve had the virus at some point. The sample could have also skewed toward people used to seeking medical care, who live near testing centers and who can pay the roughly $100 these tests usually cost without insurance. Crush the Curve said it will not turn people away who want the tests, but cannot pay.
To Ridenhour, imperfect samples mean imperfect data, and he said it's difficult, and perhaps unwise, to make policy decisions based on that.
But Ahlquist said Crush the Curve isn’t aiming for perfection.
“I think any data that we can have as a state of Idaho that helps us understand this illness is helpful," he said.
The Idaho Department of Health and Welfare is in communication with Crush the Curve, but it said it isn’t yet sure how it’s going to use the information from antibody tests.
Testing Going Forward
Crush the Curve hopes to test 18,000 more Idahoans for coronavirus antibodies by Friday. In some places like Stanley and McCall, it’s looking to eventually test almost everyone.
Knowing the percentage of people tested who have antibodies — or the seroprevalence — could give clues as to how many people are still susceptible to the virus, said Ridenhour, who has experience modeling disease outbreaks for the Centers for Disease Control and Prevention. But to find out where we are on the curve, he said the basic nasal swab tests are much better.
"That's the kind of data that’s really useful," Ridenhour said, "knowing that we have this many infectious people in our population at the time.”
As Idaho begins opening up piece by piece and people start moving around more, experts expect there will be more positive cases. Tests that look for the active virus can determine if there's an uptick and can be used to isolate confirmed cases or those who might've been exposed.
Ahlquist agrees that the PCR or nasal swab tests are the most important, and increasing their availability in Idaho is why Crush the Curve was founded.
As for Leigh, she said she wouldn’t have gotten the COVID-19 antibody test if she had been able to get a test when she was sick.
Find reporter Rachel Cohen on Twitter @racheld_cohen
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