Abstract
The main form of COVID-19 transmission is via “oral-respiratory droplet contamination” (droplet: very small drop of liquid) produced when individuals talk, sneeze, or cough. In hospitals, health-care workers wear facemasks as a minimum medical “droplet precaution” to protect themselves. Due to the shortage of masks during the pandemic, priority is given to hospitals for their distribution. As a result, the availability/use of medical masks is discouraged for the public. However, for asymptomatic individuals, not wearing masks in public could easily cause the spread of COVID-19. The prevention of “environmental droplet contamination” (EnvDC) from coughing/sneezing/speech is fundamental to reducing transmission. As an immediate solution to promote “public droplet safety,” we assessed household textiles to quantify their potential as effective environmental droplet barriers (EDBs). The synchronized implementation of a universal “community droplet reduction solution” is discussed as a model against COVID-19. Using a bacterial-suspension spray simulation model of droplet ejection (mimicking a sneeze), we quantified the extent by which widely available clothing fabrics reduce the dispersion of droplets onto surfaces within 1.8 m, the minimum distance recommended for COVID-19 “social distancing.” All textiles reduced the number of droplets reaching surfaces, restricting their dispersion to <30 cm, when used as single layers. When used as double-layers, textiles were as effective as medical mask/surgical-cloth materials, reducing droplet dispersion to <10 cm, and the area of circumferential contamination to ~0.3%. The synchronized implementation of EDBs as a “community droplet reduction solution” (i.e., face covers/scarfs/masks and surface covers) will reduce COVID-19 EnvDC and thus the risk of transmitting/acquiring COVID-19.
Highlights
The main form of COVID-19 transmission is via “oral-respiratory droplets” produced when individuals talk, sneeze, or cough
Because viruses replicate intracellularly in bodily fluids, in association with other microorganisms [23, 24], and need droplets to facilitate their expulsion, transmission, and environmental droplet contamination” (EnvDC) [12], we first validated a rapid spray-simulation model of droplets using a bacterial-suspension to quantify the extent by which widely-available household textiles reduced the ejection/long-distance flight of droplets
Because COVID-19 cases increase daily, and the fabrication of environmental droplet barriers (EDBs) by centralized organizations could take weeks to reach entire “lockdown” communities, we suggest, based on the cotton/polyester EnvDC effectiveness, and a homemade EDBmask fabrication trial (Supplementary Figure 6), that, from one piece of clothing, every individual could make two 2-layer-EDB masks as an immediate, synchronized contribution to reduce COVID-19 EnvDC
Summary
The main form of COVID-19 transmission is via “oral-respiratory droplets” produced when individuals talk, sneeze, or cough. Despite the magnitude of the COVID-19 pandemic, it is disconcerting that the general public either does not have personal protective equipment available to them, including respiratory masks, or chooses to not use them, to contain the pandemic. Health-care workers wear medical masks as a minimum “droplet precaution” to protect themselves. Regardless of clinical presentation, COVID-19 transmits person-to-person, including children [3], via “oral-respiratory droplets” produced when individuals talk or sneeze/cough. Aside from Asia [4], there are no global guidelines promoting wearing masks in public to control respiratory pandemics [5,6,7,8,9,10], and no scientific data/guidelines exist promoting masks as a “droplet precaution” for the public [5, 9, 11]
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