There are two ways to know if you’ve had COVID-19.
The first a positive nasopharyngeal swab test.
These are the tests that have been used from the beginning of the pandemic to confirm that the symptoms shown by patients are, in fact, caused by the coronavirus that emerged in late 2019.
It involves shoving a long swab through a nostril to collect a specimen at the back of the nasal cavity. The state has slowly ramped up testing, from an average of 1,414 tests each day in mid-April to an average of 4,728 per day through the first four days of this week.
Those tests are integral to Missouri’s approach to gradually restarting economic activities. The swab tests are able to detect the presence of a live virus.
In late April, the Department of Health and Senior Services deployed that type of test at Triumph Foods in St. Joseph, among other hotspots, as part of the state’s “boxed in” strategy for COVID-19 containment.
Out of 2,367 workers tested on site, 412 showed positive results despite showing no related symptoms.
The high proportion of asymptomatic cases of COVID-19 is a reason one Columbia company is eyeing the market for the second type of test – the serological test or antibody test. Although the antibody test can’t detect a live virus, it is able to show if a person was exposed to COVID-19 even if they never showed symptoms.
HELIX Specialty Diagnostics began offering the test to Missouri employers May 11.
“The nasopharyngeal test is a snapshot,” Vice President of Technology William Thornton said. “It doesn’t tell you if you had it three weeks ago and or if you’ll get it tomorrow.”
Quest Diagnostics in Columbia is also able to process antibody tests.
According to the Centers for Disease Control and Prevention, it’s still unclear if the presence of antibodies means a person has enough immunity to withstand a second exposure to the virus. That said, many, including Thornton, see antibody testing as key to resuming business as usual.
“Part of our mission when we headed down this path … was to help employers get their employees back to work,” he said.
HELIX is offering the test for $100 per kit. So far, at least eight businesses have requested the tests, six of which are in Columbia. The other two are located in the Kansas City region. HELIX President Michael Paulson said the lab is currently in discussions with several other businesses and one city.
The company is able to process 400 tests a day, but has not yet reached capacity. It’s also able to expand testing capacity if demand increases.
Still, some businesses are cautious. The antibody tests currently on the market have been certified by the U.S. Food and Drug Administration with an emergency use act (EAU).
“You see it (an emergency use act) a lot,” Lisa Thomas, a nurse at the Saline County Health Department said. “It’s kind of that desperate times call for desperate measures.”
Thornton said the tests acquired by HELIX Specialty Diagnostics have filed an emergency use act request, but at the time of speaking it had yet to be published on the FDA’s EAU page.
The FDA is working with other federal organizations to validate the accuracy of certain antibody tests. For now, though, EAU certification is the most official certification an antibody test can receive.
Matt Steele, vice president of operations at ThermAvant Technologies, LLC in Columbia said his company has discussed offering antibody testing to its employees, but is waiting on a more official ruling on the tests.
“We agreed to wait for the FDA approved antibody testing to come out since the early consensus on the testing for antibodies has been inconclusive … on the early reports we have read about,” he said.
UNDERSTANDING THE OUTBREAK
Although antibody testing could prove useful in understanding how COVID-19 spread through specific communities, many public health officials are still cautiously optimistic of its use.
Lucio Bitoy, the community relations specialist for the Columbia/Boone County Department of Health and Human Services said it’s important to understand the shortcomings of antibody testing.
A swab test can only detect a live infection and can’t tell a person if he or she has been previously exposed. An antibody test will only detect past exposure, long enough in the past for the body immune system to react. It can’t be used as a diagnosis for COVID-19. It’s also unclear the extent to which antibodies provide immunity.
But that doesn’t mean antibody testing won’t be integral to understanding COVID-19. Bitoy said from an epidemiological perspective, testing for antibodies will give public health officials a better idea of how the illness spreads through a community, which could help them respond to a future outbreak.
“We are looking into how we could utilize it here for this purpose,” he said. “But it is important for people to realize those caveats.”
Health departments have yet to roll out any antibody testing strategy.
“I’m hoping the state can give us a little more direction,” Saline County Health Department Administrator Tara Brewer said. “When it comes to that, I don’t want to purchase anything that isn’t legit.”
As of Thursday evening, at 5 p.m. there were 241 known cases of COVID-19 in Saline County, 1,058 cases per 100,000 people, the highest in the state.
Brewer and her team were also part of the state’s “boxed in” strategy, deploying more than 200 tests to those without symptoms last month. While staff has worked to track and control the local outbreak they’ve had several residents describe COVID-19-like symptoms as early as January and February. Some have even reported some of COVID-19’s unique symptoms like loss of taste or smell.
“We’ve heard that story over and over,” Thomas said.
An antibody test won’t tell Thomas or Brewer when exactly exposure took place, but when combined with patient testimony, it could give them a better idea of when active cases began to arise in Saline County.
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“I think once you interview these people and they tell you when they had symptoms and if they indeed do have antibodies, I think that would be a fair conclusion,” Thomas said.
Thomas is fairly confident antibody presence does indicate some degree of immunity. The problem with viruses, she is, is they tend to mutate as more people become immune to them.
“It’s how they (viruses) survive,” Thomas said. “They change on us.”
She is hopeful, though, that antibody testing will help health care professionals identify who is eligible to give plasma. Administering plasma with COVID-19 antibodies to patients fighting the active virus has been anecdotally shown to improve patient outcomes.
“We had a patient in particular from Saline County who was doing very poorly. He was on a ventilator and he received plasma from a donor that had had COVID already,” Thomas said. “Something improved his condition miraculously. It definitely made a difference in his prognosis.”
NOT ALL TESTS CREATED EQUAL
Testing, whether for the active virus or antibodies, will continue to be highly discussed as jurisdictions grapple with what the next phase of COVID-19 containment looks like. As of now, no test predicts absolute safety from the virus.
Brewer’s staff has had to talk employers out of requiring a negative nasopharyngeal test before allowing employees who have previously tested positive for the disease to return to work. The test picks up viral RNA, which a person can shed even without being contagious.
“Unfortunately, you might not get that for several weeks,” Thomas said. “I understand that people need to see a negative. Unfortunately, they don’t see one very quickly.”
In this case, an antibody test would tell the person what they already knew – they had the disease, a waste of resources according to Saline County Health Department staff.
What Thomas knows, however, is that COVID-19 will likely be of concern for an extended period of time and both tests will be helpful in understanding its spread.