As more data becomes available from “whole-herd” PCR testing of populations with COVID-19 outbreaks, experts are discovering a wide range in the number of people infected by the virus.
The interesting part? Dr. Jeremy Cauwels, senior vice president of quality for Sanford Health, a healthcare system covering the upper Midwest, says within the infected individuals, a high percentage can't think back and identify having any sort of cold- or flu-like symptoms.
“The asymptomatic rate is remarkably high,” Cauwels says.
Cauwels’ office is headquartered in Sioux Falls, S.D., where he has been studying the disease and its transmission. Not long after the COVID-19 outbreak among employees at a Sioux Falls pork packing plant, Cauwels became acquainted with swine veterinarians Tim Loula of Swine Vet Center and Dave Bomgaars of RC Family Farms on a conference call between medical doctors and these veterinarians discussing ways to safely reopen businesses and get people back to work.
Loula and Bomgaars believed that these essential businesses could become a model for the rest (non-essentials) to get back to normal.
Since those meetings, more and more plants have been testing their entire workforce. And the results have been eye-opening.
“For instance, in a couple of the plants that we looked at, we've tested north of 1,500 to 2,000 people. We're seeing hospitalizations from those plants of maybe 10 to 20 people at most, which is a remarkably smaller number than the initial estimates of a 20% symptomatic rate in the population with a hospitalization rate of 20% of that group,” Cauwels explains. “We are still seeing people with symptoms, but many of them are mild.”
That’s probably why this disease spreads so easily – people don't think they're really that sick. Unlike influenza, which often hits people like a ton of bricks, COVID-19 doesn’t act that way, he adds.
“Few are complaining and calling in sick from work, other than the first couple of index patients who alerted us a facility may have an outbreak,” Cauwels says.
Missouri Director of Agriculture Chris Chinn, a pork producer from Missouri, says the Triumph Foods pork packing plant voluntarily PCR tested their employees as part of a new strategy in Missouri to deploy COVID-19 test kits to a potential hot spot in an effort to prevent a massive outbreak within a community. Of the employees who tested positive for COVID-19, a high percentage were walking around with no symptoms.
“I think it paid off for them because they were able to find people who might be shedding that virus, and isolate them to protect the rest of the workforce,” Chinn says. “They were able to maintain keeping their doors open, keeping people working and making sure that there was food on the table of all Missourians.”
Stop blaming packing plants
Packing plants aren’t havens for COVID-19. Cauwels says it’s one of the biggest misconceptions about the spread of COVID-19.
“This disease is out in populations in general. It just so happens to spread faster through people who are working closely together,” he says.
In addition, large population testing isn’t happening in other plants like it is in meat processing plants, Chinn says.
Veterinarians and doctors have a similar way of working through disease management, Cauwels adds. During the meetings with Loula and Bomgaars, he says they had to shift gears from worrying about a population of animals to a population of people. But at the end of the day, it all comes down to the effect of a disease on individuals and populations. How do we keep them as safe as possible?
“I think the thing that surprised me the most was just trying to understand the dynamics of how people live and work and get back and forth to places every day. Many people don't go to work individually in their own car and come back individually in their own car to a single-family dwelling,” Cauwels says. “Understanding how that can affect disease spread, much like a New York subway could affect disease spread, was one of the things I had to wrap my head around fairly quickly.”
Employers can’t control what their employees do when they aren’t at work, Chinn says.
“In many of these processing plants, what they found is that where they had the positives, they weren't people who were working side by side. So you can't say that it only happened at work or it only happened in the community,” Chinn adds.
Efforts to test populations in meat packing plants has helped advance understanding of COVID-19. Up to this point, the gold standard to determine if someone has COVID-19 has been a PCR test.
“The PCR test looks for pieces of virus generally found in somebody's nose. That test is currently being expanded to try to find it in other body fluids and other places like in the mouth because the nasal swab isn't particularly comfortable,” Cauwels says.
The second test used is the antibody test, which is a bit more complex. There are at least four other strains of Coronavirus that cause things like the common cold, he explains.
The challenge has been that current antibody testing has difficulty distinguishing the usual four strains of Coronavirus, including SARS and MERS, from COVID-19. Cauwels says this has been a stumbling block for many labs. Newer tests are coming out and are more available day by day in different hospitals and clinics.