Rapid evidence summary on SARS-CoV-2 survivorship and disinfection, and a reusable PPE protocol using a double-hit process

Abstract

In the COVID-19 pandemic caused by SARS-CoV-2, hospitals are stretched beyond capacity. There are widespread reports of dwindling supplies of personal protective equipment (PPE), which are paramount to protect frontline medical/nursing staff and to minimize further spread of the virus. We carried out a rapid review to summarize the existing evidence on SARS-CoV-2 survivorship and methods to disinfect PPE gear, particularly N95 filtering facepiece respirators (FFR). In the absence of data on SARS-CoV-2, we focused on the sister virus SARS-CoV-1. We propose a two-step disinfection process, which is conservative in the absence of robust evidence on SARS-CoV-2. This disinfection protocol is based on an initial storage of PPE for ≥4 days, followed by ultraviolet light (UVC), dry heat treatment, or chemical disinfection. Importantly, each of the two steps is based on independent disinfection mechanisms, so that our proposed protocol is a multiplicative system, maximising the efficacy of our disinfection process. This method could be rapidly implemented in other healthcare settings, while testing of each method is undertaken, increasing the frontline supply of PPE, and avoiding many of the upstream issues of supply chain disruption currently being faced.

Soft matter science and the COVID-19 pandemic

“…The use of ultraviolet (UV) radiation also becomes possible for fomite sanitising. The recommendation 171 is to use the UVC band (below 280 nm). Here, it is important to note that both NaCl and proteins absorb strongly below 300 nm, so that viruses encrusted in salt and mucin are likely somewhat protected against UVC.…”

Upper-room ultraviolet air disinfection might help to reduce COVID-19 transmission in buildings: a feasibility study

“…Since the emergence of COVID-19 in January 2020 there has been considerable interest in the use of ultraviolet (UV) light to disinfect blood plasma ( Eickmann et al, 2020 ; Keil et al, 2020 ; Ragan et al, 2020 ), equipment ( Card et al, 2020 ; Derraik et al, 2020 ; Hamzavi et al, 2020 ; Heimbuch & Harnish, 2019 ) and air ( Morawska et al, 2020 ), in the hope that this might reduce transmission of the disease. In particular, upper-room ultraviolet germicidal irradiation (UVGI), a technology that disinfects room air, has been muted as a potential intervention that might prove effective against COVID-19 ( Morawska et al, 2020 ; Nardell & Nathavitharana, 2020 ; Skorzewska, 2020 ).…”

The Use of UVC Irradiation to Sterilize Filtering Facepiece Masks Limiting Airborne Cross-Infection

“…The main issue in the design of the device was to determine the required minimum exposure time to disinfect the surface, so as to effectively deactivate the pathogen-containing particles, as well as the maximum exposure time, exceeding which could cause permanent damage to the filter surface. As demonstrated in previous studies [ 6 , 8 , 9 ], a sterilization dose of approximately 1 J/cm² is sufficient to sterilize the surface of the material. It has also been shown [ 8 , 10 ] that increasing the radiation dose above 1 J/cm² does not bring significant benefits.…”

“…Looking at the general similarities between the currently spreading SARS-CoV-2 and SARS-CoV and MERS-CoV, it can be presumed that UVGI is also effective in deactivating SARS-CoV-2. The problem of deactivating the pathogen by UVC radiation can be also found in many recent publications [ 3 , 4 , 5 , 6 ]. The primary purpose of our research is to develop the device and determine its effectiveness.…”