MultiMaskers — Benefits of Wearing 2+ Masks
President Biden, Amanda Gorman, the Secret Service, Dr. Jarryd Willis, & others have been MultiMasking
For maximal protection (Gandhi & Marr, 2020)
2 Masks at the same time → (1) wear a cloth mask tightly on top of a surgical mask where the surgical mask acts as a filter and the cloth mask provides an additional layer of filtration while improving the fit.
To quote Elizabeth Hanes of WebMD, “if you’re using a basic cotton mask, wearing a second mask might indeed trap more viral particles in your breath when you exhale and might also provide better protection against inhaling the virus from the air.”
USA Today → “…some, including President-elect Joe Biden, have been seen wearing multiple masks at once. Experts say that this is an extra step that can help limit any “leakage” of air… a second mask may reduce ‘leakage’ and could be a reasonable thing to do, particularly for public-facing employees such as teachers, grocery cashiers and bus drivers,” said Dr. Sten Vermund, dean of the Yale School of Public Health in New Haven, Connecticut.”
3-Layer Mask → (2) wear a three-layer mask with outer layers consisting of a flexible, tightly woven fabric that can conform well to the face and a middle layer consisting of a nonwoven high-efficiency filter material.
(CNN) → “Home-made cloth face masks likely need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets from the nose and mouth that are associated with the spread of COVID-19,”
By, Multimasking can protect individuals from COVID19 acquisition by further reducing inhalation of viral particles by the mask wearer. Moreover,
“multiple layers of fabric have been found to substantially increase the filtration efficiency of mask materials (Drewnick et al., 2020; Zangmeister et al., 2020), with the first layer reducing the velocity of the droplets and increasing the ability of the second layer to filter the droplets” (Aydin et al., 2020)
“If the masks fit well, these combinations should produce an overall efficiency of >90% for particles 1 mm & larger, which corresponds to the size of respiratory aerosols that we think are most important in mediating transmission of COVID19” (Pan et al., 2020).
Beyond the impact on COVID-19 transmission rates, Gandhi & Marr (2020) and others posit that facial masking reduces the size of the viral inoculum to which people are exposed. Thus, if they become infected while wearing a mask, the mask would decrease the severity of their COVID-19 infection. Stated differently,
if someone becomes infected while wearing a mask, they are more likely to have a milder or asymptomatic infection than someone who becomes infected while not wearing a mask (Gandhi & Marr, 2020)
Caveats → successful multimasking requires avoiding any of the following outlandish/ unrealistic/ unlikely to ever happen behaviors:
- wearing a secondary mask with strings that aren’t long enough to fit over the primary
- playing with the strings (some article actually mentioned this… it’s like they have to create/ make-up issues with multimasking)
- “Dr. S. Patrick Kachur, a professor at the Columbia University Mailman School of Public Health in New York City, said that some combinations, such as a mask and a neck gaiter, could be more effective than the singular gaiter, since some gaiters are just one layer of fabric. If you’re layering two masks you should make sure you have enough to rotate them in and out and wash them regularly,” Kachur added.”
Make sure you have enough → I have about 20+ fashion masks lols
Failing to wear the mask properly will result in a reduction in efficiency (Dbouk & Drikakis, 2020). This is because…
air flow will preferentially follow the path of least resistance [Drewnick et al., 2020), and smaller droplets will likely follow this path around the mask (Dbouk & Drikakis, 2020), regardless of filtration efficiencies (Buxton et al., 2020)
Beyond 6 Feet (Verma et al., 2020)
The pathogen responsible for COVID19 is found primarily in respiratory droplets that are expelled by infected individuals during coughing, sneezing, talking, and breathing10–15. SARS-CoV-2 is spread through the presence of infectious SARS-CoV-2 virions in respiratory aerosols/droplets emitted from an infected individual & depositing in the respiratory tract of a susceptible individual (Lednicky et al., 2020; Santarpia et al., 2020). Coughs and sneezes result in violent, episodic pu releases (Bourouiba et al., 2020) while speaking and singing result in a pu train that may be well approximated as a continuous turbulent jet (Asadi et al., 2019; Abkarian et al., 20202).
Masks and other face coverings are effective in stopping larger droplets, which although fewer in number compared to the smaller droplets and nuclei, constitute a large fraction of the total volume of the ejected respiratory fluid.
Regardless of their size, all droplets and nuclei expelled by infected individuals are potential carriers of pathogens.
The smaller droplets may be a larger concern given that…
1 →The smallest droplets can remain suspended in the air for hours after the infected individual has left the area, potentially infecting unsuspecting individuals who come into contact with them
2 → They can penetrate deep into the airways of individuals who breathe them in, which increases the likelihood of infection even for low pathogen loads.
Droplet dispersal of uncovered coughs were able to travel noticeably farther than the currently recommended 6-foot distancing guideline.
Verma et al,. 2020 Results:
We observed high variability in droplet dispersal patterns from one experimental run to another, which was caused by otherwise imperceptible changes in the ambient airflow. This highlights the importance of designing ventilation systems that specifically aim to minimize the possibility of cross-infection in a confined setting.
the ejected tracers were observed to travel up to 12 feet within approximately 50 seconds. Moreover, the tracer droplets remained suspended midair for up to 3 minutes in the quiescent environment.
Verma, S., Dhanak, M., & Frankenfield, J. (2020). Visualizing the effectiveness of face masks in obstructing respiratory jets. Physics of Fluids, 32(6), 061708.
Buxton et al., 2020: One study has estimated that the economic benefit of each additional cloth mask worn ranges from $3,000 to $6,000 (Abaluck et al., 2020) stemming, in part, from the recovery of the estimated $60,000 per capita mortality risk (Greenstone & Nigam, 2020).
The use of masks is also expected to reduce the formation of fomites by limiting the emission of large droplets from infected individuals (Huang et al., 2020).
Face Shield → the smaller droplets move around the face shield and do not interact with the face shield at all. The collection efficiency for the face shield is very small, because all but the largest droplets follow the air flow around the face shield” (Buxton & Minutolo, 2020).
The “infective dose” = “the number of aerosol-borne virions required to cause infection. Replication of SARS-CoV-2 is more apparent in droplets with radii r< 2.05µm, despite a nearly uniform viral load across all drop sizes” (Santarpia et al., 2020).
R0 = The reproduction number of an epidemic is defined as the mean number of transmissions per infected individual.
To minimize risk of infection, one should avoid spending extended periods in highly populated areas. One is safer in rooms with large volume and high ventilation rates. One is at greater risk in rooms where people are exerting themselves in such a way as to increase their respiration rate and pathogen output, for example by exercising, singing or shouting.
Since the rate of inhalation of contagion depends on the volume flux of both the exhalation of the infected individual and the inhalation of the susceptible person, masks worn by both infected and susceptible persons will reduce the risk of transmission by a dramatic factor (Konda et al., 2020; Oberg et al., 2008).
The breathing flow rate is assumed to be .5 m3/h for nose & mouth breathing, 0.75 m3/h for whispering and speaking,
and 1.0 m3/h for singing (Bizant & Bush, 2020)
COVID & Cute Kittens
14. Hök K. Demonstration of feline infectious peritonitis virus in conjunctival epithelial cells from cats. APMIS 1989; 97: 820–824.
15. Van Hamme E, Desmarets L, Dewerchin HL et al. Intriguing interplay between feline infectious peritonitis virus and its receptors during entry in primary feline monocytes. Virus Res 2011; 160: 32–39
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