Track COVID-19 Asymptomatic Carriers Through Environmental Tests

Back in the first week of March, a client of mine and I were discussing the cases of COVID-19 recently found in New York City. My client was a medical doctor and worked at a large hospital in the area so I was interested on his take on stopping the spread of the coronavirus. I had mentioned that I thought the steps similar to what airports in Turkey were taking to screen COVID-19 carriers would be enough to stop the spread, which was to thermally scan passengers before boarding and after their flights. If you had a fever, you were questioned and quarantined. Since having a fever was one of the first symptoms of the disease, it seemed like an effective solution. My client slowly shook his head and said “Thermal screening is not going to be effective. COVID-19 is being spread by people who show no symptoms, so there is no way to screen for these carriers”. I decided then that I was not going to be traveling anytime soon.

As it turns out, my client was prescient on COVID-19’s spread by asymptomatic carriers. After some initial skepticism from the medical community, recent studies have shown that up to 50% of COVID-19 cases have been spread through asymptomatic carriers. One obvious way to catch these carriers is through a continual testing program of all employees, but is there another feasible alternative to continually testing everybody?
A recently presented case study from the Washington Health Care Association (WHCA) and Enviral Tech suggests there is a COVID-19 tracking alternative. The study looked at over 50 long-term care facilities and whether COVID-19 testing of surfaces would be an effective tool at discovering and controlling COVID-19 outbreaks in those facilities. The study focused on the concept of ‘viral shedding’ and how the COVID-19 virus is spread from infected persons through either by droplets, or by aerosol onto environmental surfaces (counters, tables, chairs, door handles, etc.). The study included the collection and testing of hundreds of surface samples.

The results of the study indicated that not only was surface testing effective in showing whether COVID-19 was present at a facility, the surface testing results were used to prevent a wide-spread outbreak at two of the facilities in the study. In both cases, when there was a positive surface test result, the facilities conducted COVID-19 testing of all staff and were able to identify and isolate the asymptomatic carriers.

These study results indicate that environmental surface testing for COVID-19 is effective at identifying facilities with asymptomatic carriers and can be part of a feasible, effective strategy in tracking and stopping the spread of the virus within a facility.

Robert J. Carr, P.E., LEP is Vice President and Principal Environmental Engineer at East-West Engineering, Inc. He can be reached at bob.carr@east-westengineering.com, or by phone 860-709-9253.

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