Last-resort strategies during mask shortages: optimal design features of cloth masks and decontamination of disposable masks during the COVID-19 pandemic

Abstract

Face masks and respirators are the most widely used intervention measures for respiratory protection. In the wake of COVID-19, in response to shortages and lack of availability of surgical masks and respirators, the use of cloth masks has become a research focus. Various fabrics have been promoted with little evidence-based foundation and without guidelines on design principles for optimal performance. In these circumstances, it is essential to understand the properties, key performance factors, filter mechanisms and evidence on cloth masks materials. The general community might also need to decontaminate and reuse disposable, single-use devices as a last resort. We present an overview of the filter materials, filter mechanisms and effectiveness, key performance factors, and hydrophobicity of the common disposable masks, as well as cloth masks. We also reviewed decontamination methods for disposable respiratory devices. As an alternative to surgical masks and respirators, we recommend a cloth mask made of at least three layers (300–350 threads per inch) and adding a nylon stocking layer over the mask for a better fit. Water-resistant fabrics (polyesters/nylon), blends of fabrics and water-absorbing fabrics (cotton) should be in the outside layer, middle layer/layers and inside layer, respectively. The information outlined here will help people to navigate their choices if facing shortages of appropriate respiratory protection during the COVID-19 pandemic.

Community Knowledge About the Use, Reuse, Disinfection and Disposal of Masks and Filtering Facepiece Respirators: Results of a Study Conducted in a Dermatology Clinic at the University of Naples in Italy

“…Hence, cloth mask use may be proposed in community settings in case of unavailability of other facial masks [ 22 ]. In the pandemic period, one of the last resort strategies during mask shortages has been represented by masks decontamination and reuse [ 23 ]. Indeed, many strategies to disinfect and to sterilize masks have been suggested to the population in order to be able to reuse masks.…”

Is it Possible to Mechanical Recycle the Materials of the Disposable Filtering Masks?

“…Theoretically, the disposable mask could be disinfected and sterilized for direct reuse [ 10 , 11 , 12 , 13 ], but possible other contaminations and reduction in the filtering effectiveness make it difficult and not recommended by scientific technical committees. A second solution is to recycle the materials of which the masks are made, which is the central focus of this article.…”

“…It is therefore apparent from a medical point of view that, even if the masks were from infected subjects, the virus would no longer persist after 10 days. Any further treatment for disinfection would have to be deeply evaluated but already studied by several researchers [ 10 , 12 , 13 , 15 , 16 ].…”

“…In this article, the validation of the recycling idea was carried out using only new disposable face masks, but it should be the basis for the use of disinfected masks after use by a separate collection circuit that some municipalities want to implement. Obviously, many producers and many types of masks are present on the market, and an exhaustive investigation of everything that may be present is extremely difficult (e.g., 94 companies and 196 products present in an online database [ 17 ] and other researches [ 13 , 18 , 19 ]).…”

Association between COVID-19 Outcomes and Mask Mandates, Adherence, and Attitudes

“…Even though we control for state-specific trends, here we investigate the heterogeneity of treatment effect between earlier and later-wave states as it is possible that the effect of mask mandates on states that were part of the COVID-19 pandemic’s early wave might be different from states that were affected later. For example, mask shortages were present during the early stages of the pandemic [67–69] which might affect the proportion of people who wear masks (mask adherence) following a mask mandate for early states compared to later states. Therefore, as a robustness check, we recompute our treatment effect estimates but this time looking separately at the first 15 states to have the highest number of cases per 100K during the month of April (namely, NY, NJ, MA, CT, MI, DC, RI, IL, WA, PA, GA, VT, MD, FL, LA) compared to the rest of the states (i.e.…”