Health officials track COVID-19 patients showing no symptoms

Officials say 412 employees at a Missouri pork-processing plant have been diagnosed with coronavirus — though all are asymptomatic, or show no signs of the illness.

Triumph Foods, in St. Joseph, begun to implement companywide testing of its asymptomatic employees in late April, amid news of several large meat-processing facilities across the nation being forced to temporarily close due to COVID-19 outbreaks, or staffing shortages created by the pandemic.

Triumph Foods did not provide information on how many employees with symptoms have tested positive,  though the CEO of the company estimated 90 percent asymptomatic in a video posted Sunday.

"We're seeing a really interesting array of presentations -- from no symptoms at all to people dying of overwhelming pneumonia and sorts of things in between," says Dr. David Aronoff, Director of Infectious Diseases at Vanderbilt University Medical Center.

Aronoff said those who tested positive but showed no symptoms could still get sick.

"They’re in a window where they test positive, they’re shedding virus and they are infected but they haven’t developed symptoms and maybe they will."

Or, experts say, they won't recognize the symptoms as those of coronavirus.

"If we're only asking about fever, cough, shortness of breath, then we are missing a big fraction of people who have other symptoms," explains Dr. Nicole Iovine, Hospital Epidemiologist in Chief at the University of Florida.

In Orange County, officials say about 10 percent of the people who tested positive for CO ID-19 didn’t show any symptoms. Dr. Nicole Iovine says their numbers have been even lower.

"We have found in the order 2 or 3 % in the group we’ve looked at -- with no symptoms -- are testing positive.

But what about all the people who have not been tested?  Many communities now ramping up antibody testing, which could give a clearer picture of who has already had the virus but didn’t know it at the time.

"One of the important goals of public health is to understand the size and scope of a pandemic like this," says Dr. David Aronoff. "If were going to base policies like opening stores again, or getting crowds together at sporting events those sorts of really would be helpful to know the behavior of the infection."