CSU team finds dozens of asymptomatic nursing home workers infected with coronavirus

Dr. Nicole Ehrhart and Greg Ebel had their big "ah-ha" moment a few weeks into testing hundreds of skilled nursing facility workers for the coronavirus.

The facilities, used to taking precautions against things like seasonal flu outbreaks, seemed to be doing everything right. No visitors were allowed in. Employees of the five Denver metro area living communities were screened for coronavirus symptoms each day they reported to work. Management was following guidance from the state and Centers for Disease Control and Prevention.

But as the test results came back, it became clear that dozens of infected workers were showing no symptoms at all. Of 462 employees tested in the first two months of the Colorado State University project, 57 people (about 12.3%) were coronavirus-positive but had no symptoms. The positive rate at the five facilities ranged between 1% and 23%.

“Most people in our study who are virus positive are not sick," said Ebel, a CSU professor in the Department of Microbiology, Immunology and Pathology whose lab processed the tests. "And they’re really virus-positive. They’re not just kind of, a little bit positive. There is no doubt that they're very positive and capable of transmitting."

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Ebel teamed up with Ehrhart, director of the Columbine Health Systems Center for Healthy Aging at CSU, to test asymptomatic workers at five Vivage skilled nursing facilities. They started the project before it was known that many people infected with the virus never develop symptoms. The project was also unique because they tested participants weekly, allowing for a better understanding of how the virus spreads in an area over a longer timeline.

The pilot project served as the proof of concept for a statewide collaboration with CSU that is in the final planning stages. The larger project will test workers and residents of 25 more skilled nursing facilities weekly for eight weeks.

The hope is to learn more about coronavirus transmission and wrangle the growth of outbreaks at skilled nursing and assisted living facilities, which account for close to 56% of the virus’s death toll in Colorado. That’s over 500 lives lost so far across 120 facilities.

The surveillance testing approach was effective in the pilot phase of the project. The rate of new infections started to decline about two weeks after testing began. Workers who tested positive were isolated and retested weekly, resuming work once they tested negative.

“We believe we have really influenced a hidden threat in these homes that nobody really knew about,” Ehrhart said.

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The primary goal of the study was to protect residents of long-term care facilities, who typically fall in the high-risk group for coronavirus infection because they’re older and often have comorbidities like high blood pressure or heart and lung disease. Add those risk factors to the relatively close quarters characteristic of any congregate living situation and the residents’ need for hands-on care, and you get “a very, very ripe environment for any kind of infectious disease,” Ehrhart said. 

There’s a misconception that the coronavirus is spreading at nursing facilities because of carelessness, Ehrhart said. She conceded that could be the case at select facilities, but she doesn’t think poor care is driving the majority of the outbreaks.

“These are places where fuel for a fire is just waiting, and all it takes is a little spark,” Ehrhart said. “So we’re trying to get rid of the spark, if this is the spark.”

The secondary goal of the pilot study is to learn more about the virus and how it’s spread — familiar questions to Ebel, who’s spent his career studying West Nile virus. Ebel’s lab has been working to sequence the RNA of virus samples, which allows them to track small mutations that reveal the virus’s path from person to person. The coronavirus, like other viruses, evolves and mutates rapidly. The mutations don’t necessarily make it more or less dangerous, Ebel added, but they can be revealing.

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“If we have a facility with a lot of infections and they all have similar sequences, it’s evidence they came from the same source,” Ebel said. “If they look different, that’s evidence it came from outside.”

The prevalence of infection without symptoms also underlines the importance of using social distancing procedures as retailers and workplaces reopen, Ebel said. Screening people for symptoms before they enter these spaces won't catch asymptomatic people who could still spread the virus.

Ebel and Ehrhart hope the lessons they’re learning can be applied to other complex work and living spaces, from meatpacking plants to universities.

“In a way, it’s a little microcosm of what can happen and what maybe should happen,” Ehrhart said. “It can inform us about how we can get back to work and how we can protect ourselves, our communities, our coworkers, all of that.”

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The testing approach could be especially valuable for skilled nursing facilities, where isolation isn't a realistic long-term strategy for residents, Ehrhart said.

"You can’t keep people in isolation forever, and truthfully, while they may be isolated from their family, they’re still not isolated from the workers," she said. "Everybody uses precautions, but the truth is, there's nobody in a skilled nursing facility that doesn’t need care. You wouldn't be there if you didn't need care."

Jacy Marmaduke covers government accountability for the Coloradoan. Follow her on Twitter @jacymarmaduke. Support stories like this one by purchasing a digital subscription to the Coloradoan.​​​​​​​