Coronavirus spread study points to your shoes

Chris Burns - Apr 13, 2020, 12:15 pm CDT
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Coronavirus spread study points to your shoes

CDC social distancing rules suggest 6 feet of distance for the average citizen of the United States during our current global pandemic. A study set for “Early Release” in the CDC’s Emerging Infectious Diseases journal suggests that a mere 6 feet is not far enough. This study suggests instead that “maximum transmission distance of SARS-CoV-2 aerosol” could be up to 4 meters (13 feet.)

Studies test for spread

A series of studies were carried out in the first months of the year 2020 and beyond as COVID-19 spread around the earth. This study tested for SARS-CoV-2, the name of the virus that causes the COVID-19 disease. In this latest study, we see more confirmation that a 6-foot range between you and the people around you isn’t enough to avoid the spread of SARS-CoV-2 / COVID-19.

This is one of several studies that says sneezes can travel 6-7 feet, but aerosols go further. That’s the part that travels up to and including 30-feet, according to at least one study. Dr. Bourouiba published findings earlier this year that suggested 23-26 feet for sneezes is also a valid concern.

The latest study / spread

The newest study worked with with samples from Huoshenshan Hospital in Wuhan, China. Researchers collected samples from an intensive care unit (ICU) as well as a general COVID-19 ward (GW) at the hospital.

During the study’s collection period, the ICU housed 15 patients with severe disease, while the GW housed 24 patients with milder disease. Samples were collected with a SASS 2300 Wetted Wall Cyclone Sampler (Research International, Inc.) at 300 L/min for of 30 min.

This study found high concentrations in the places you’d expect – in patent rooms, near air outlets, on some surfaces, but a LOT on the floor. This included a generous distance surrounding said patients – up to 4 meters.

Samples / Rate of Positivity
Isolation Ward
– Floor: 70%
– Computer Mouse: 75%
– Trash Can: 60%
– Sickbed Handrail: 42.9%
– Air Outlet Filter: 66.7%
Pharmacy in ward
– Indoor air: 0%
– Floor: 100%
PPE*
– Face Shield of medical staff: 0%
– Sleeve cuff of medical staff: 16.7%
– Glove of medical staff: 25%
– Shoe sole of medical staff: 50%

*PPE: personal protective equipment of medical staff in isolation ward.

It’s on the shoes

Areas designated “semicontaminated area” and “dressing room 4” had 0% positivity testing for SARS-CoV-2, except one. The floor of the dressing room showed 37.5% positivity. This combined with the shoe sole results and the floor of the pharmacy suggest that spread happens on the soles of shoes – in a big way.

Per the study, “the soles of medical staff shoes might function as carriers. The 3 weak positive results from the floor of dressing room 4 might also arise from these carriers. We highly recommend that persons disinfect shoe soles before walking out of wards containing COVID-19 patients.”


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