Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water

Abstract

To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94–3.01 log reduction in E. coli concentration without, and 2.18–3.34 with, soil load; and a 2.44–3.06 log reduction in Phi6 without, and 2.71–3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28–4.77 log reduction in remaining E. coli without, and 0.21–4.49 with, soil load and a 1.26–2.02 log reduction in Phi6 without, and 1.30–2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.

Assessing Viral Transfer During Doffing of Ebola-Level Personal Protective Equipment in a Biocontainment Unit

“…Defects in hand hygiene may be an important risk factor for HCWs to acquire EVD [28]. While the Centers for Disease Control and Prevention guidelines do not specify the hand hygiene product, the World Health Organization and Médecins Sans Frontières recommend use of 0.5% chlorine for all hand hygiene events, which has been supported by some data using Φ6 [29].…”

Determining the Efficacy, Safety and Suitability of Disinfectants to Prevent Emerging Infectious Disease Transmission

“…Efficacy: With E. coli, HTH performed most consistently well, with statistically significantly greater logarithmic reductions than other individual handwashing methods [16]. However, the magnitude of handwashing efficacy differences was small, suggesting that methods were similarly efficacious.…”

“…Efficacy: To assess the efficacy of handwashing methods, 18 volunteers' hands were spiked on four separate trial days with a non-infectious BSL-1 E. coli or the selected BSL-1 surrogate from above, with and without soil load [15,16]. For each trial, the volunteers completed seven handwashing methods, including control (nothing); water only; soap and water; sanitizer; and HTH, NaDCC, generated NaOCl and pH-stabilized NaOCl solutions.…”

Inhibitory effects of different hand sanitizers against the resident microflora of skin

“…6,7 Beside the antibacterial activity, alcoholbased hand sanitizers have been reported as one of the commonly recommended hand hygiene against the diseases outbreaks causes by Ebola-Virus. 8,9 As described by previous researchers that hand sanitizers have been found as very effective agent in order to eradicate the gastrointestinal infection as well as hospital acquired infection. 7,10 Eventually, people are now more interested to use hand sanitizer instead of only hand washing due to its better performance against the resident skin flora such as Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis.…”