Short answer: A 2020 study in the CDC journal Emerging Infectious Diseases tested air and surfaces in two hospital wards in Wuhan, China. Floors and the soles of medical staff shoes showed some of the highest contamination rates, and the researchers recommended disinfecting shoe soles before leaving wards with COVID-19 patients.
What did the study look at?
Researchers collected swab and air samples from an intensive care unit (ICU) and a general ward at Huoshenshan Hospital between February 19 and March 2, 2020. They tested floors, computer mice, trash cans, bed handrails, masks, protective equipment, and air outlets for the genetic material of SARS-CoV-2.
Key findings about floors and shoe soles
- Contamination was greater in the ICU than in the general ward.
- In the ICU, 7 of 10 floor samples (70%) tested positive, compared with 2 of 13 (15.4%) in the general ward.
- Half of the samples from the soles of ICU medical staff shoes tested positive.
- The floor in the pharmacy, where there were no patients, tested positive, which suggests the virus was carried there by foot traffic.
The authors concluded that shoe soles might act as carriers and recommended disinfecting them before leaving affected wards.
Limitations
The authors noted that their tests detect genetic material and do not show how much of the virus was viable. They also said the aerosol transmission distance could not be strictly determined.
What this means for shoe covers
The study highlights that floors and shoes can carry contaminants from one area to another. In healthcare and cleanroom settings, disposable shoe covers are one tool used to help keep outside contaminants from spreading between areas. They should be used alongside, not instead of, your facility's infection control protocols.
Source
Guo Z, Wang Z, Zhang S, et al. Aerosol and Surface Distribution of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospital Wards, Wuhan, China, 2020. Emerg Infect Dis. 2020;26(7):1583-1591. Read the full study on CDC.gov (DOI: 10.3201/eid2607.200885).
Learn more about WHO guidance on shoe covers or shop clean room rated disposable shoe covers.