Articles relating to COVID 19

General
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What is the efficacy of standard face masks compared to respirator masks in preventing COVID-type respiratory illnesses in primary care staff?

March 24, 2020

VERDICT

Standard surgical masks are as effective as respirator masks (e.g. N95, FFP2, FFP3) for preventing infection of healthcare workers in outbreaks of viral respiratory illnesses such as influenza. No head to head trial of these masks in COVID-19 has yet been published, and neither type of mask prevents all infection. Both types of mask need to be used in combination with other PPE measures. Respirator masks are recommended for protection during aerosol generating procedures (AGPs). Rapid reviews on wider PPE measures, and what counts as an AGP, are ongoing

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YO! Mr Peabody! …I’m Axe’ing you, So they keep talking Aerosols, is that Ya’ know like air freshner???

Well Sherman Yes and No, but A GREAT QUESTION as to Why YOU Should were a MASK!

Airborne Transmission of Viral Respiratory Pathogens. Don’t Stand So Close to Me?

Figure 1. Particle Settling in Turbulent Air Half-life of particles in 8 foot high room

ALL VIRAL Particles are Aerosols…(Physicists Rule…Biologist Drool!!! WOLVERINES!!!)

Actually any particle 100um and smaller are respirable and respirable. Particles up to 100 μm in size are considered inhalable (inspirable). These aerosolized particles are small enough to be inhaled into the oronasopharynx, with the smaller, respirable size ranges (eg, < 10 μm) penetrating deeper into the trachea and lung.

(Said the guy who had to buy tons of 3 to 10 micron monodisperse latex and glass micron scale spheres for bioagent dispersion and mixing tests)

SARS COV-2 125nm mean particle diameter

"One of the standard rules (Stoke’s Law) applied in engineering calculations to estimate the suspension times of droplets falling under gravity with air resistance, was derived assuming several conditions including that the ambient air is still [13,14,15,16,17].

So actual suspension times will be far higher where there are significant cross-flows, which is often the case in healthcare environments, e.g. with doors opening, bed and equipment movement, and people walking back and forth, constantly.

Conversely, suspension times, even for smaller droplet nuclei, can be greatly reduced if they encounter a significant downdraft (e.g. if they pass under a ceiling supply vent). In addition, the degree of airway penetration, for different particle sizes, also depends on the flow rate."

"For SARS-CoV, several thorough epidemiological studies that include retrospective airflow tracer investigations are consistent with the hypothesis of an airborne transmission route [39,40,41]. Air-sampling studies have also demonstrated the presence of SARS-CoV nucleic acid (RNA) in air, though they did not test viability using viral culture [42].

Although several studies compared and contrasted SARS and MERS from clinical and epidemiological angles [43,44,45], the predominant transmission mode was not discussed in detail, if at all.

Several other studies do mention the potential for airborne transmission, when comparing potential routes of infection, but mainly in relation to super-spreading events or “aerosolizing procedures”such as broncho-alveolar lavage, and/or a potential route to take into consideration for precautionary infection control measures [46,47,48].

However, from the various published studies, for both MERS and SARS, it is arguable that a proportion of transmission occurs through the airborne route, although this may vary in different situations (e.g. depending on host, and environmental factors).

The contribution from asymptomatic cases is also uncertain [49].

For both SARS and MERS, LRT samples offer the best diagnostic yield, often in the absence of any detectable virus in upper respiratory tract (URT) samples [50,51,52]. Furthermore, infected, symptomatic patients tend to develop severe LRT infections rather than URT disease. Both of these aspects indicate that this is an airborne agent that has to penetrate directly into the LRT to preferentially replicate there before causing disease."

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https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic

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:star::star:Preliminary Nuke the Mask Experiment :star::star:

Okay Mr. Wizard what was the result of your experiment.

“Help me, Mr. Wizard, I don’t want to be Contaminated any more!”

“Drizzle, Drazzle, Druzzle, Drome; time for this one to come home.”
…

Hypothesis: Disposable medical and surgical masks could be effectively steamed in an home microwave oven to reuse.

Objective: Safely steam heat different types of nonwoven fiber, cloth, and paper mask to sufficient heat with steam per prescribed CDC references. Achieve 160°F(71C) for 3 to 5 minutes without melting the plastic bag or destroying mask while saturating with steam. Secondary objectives were to not destroy the microwave, start a fire, contaminate the entire kitchen, or get thrown out of the house.

Method: Nuke the crap out of current N95 and Non N95 masks in a 1,000 Watt Microwave Oven (preferrably without destroying it or otherwise pissing off the missus) while controlling cross contamination.

Materials:

Frigidare 1KW Microwave oven 2450MHz with glass rotating stage @ 3min, 3min 30 sec, 4 min
Great Value Double Zip Quart Storage Bags
Bounty Paper Towels
Tap Water
Surgical Gloves
Needle Nose Pliers
Scotch Magic Tape
Exacto Knife
Tweezers
Kitchen Tongs
GDealer Digital probe thermometer (-50 to 300C)

Discussion:

Masks were carefully inspected and aluminum nose strip removed using Exacto knife and tweezers leaving small slot to reinsert aluminum strips. One resembled a plastic coated wire tie rather versus the flat mallable aluminum strip.

Each mask was flattened and wrapped in a fairly well saturated double thickness paper towel and inserted into the ziplock plastic bag. The mouth of the bag was closed but not zipped to let the steam escape.

Each bag was nuked (irradiated) for 3 to 4 minutes until the digital thermometer indicated 160F. The bag was left in the closed microwave for an additional two three minutes to ensure saturation and apply supplemental internal alcohol disinfectant solution to the experimental staff.

3 minute irradiation seemed to achieve good level of steam and 140° to 150°F temperature. At 3 min 30 sec 160° to 168°F was observed. At 4 minutes in the largest mask the indicated temperature was 198 to 204°F and it maintained above 165°F in the bag for 3 minutes or more. Exact temperature decay data is not clear to to additional prophylactic applications of ethanol decontamination fluid.

Noted is after 5 or more 3 to 4 successive irradiation steam sessions, minor to no puckering of the mask was noted. The bottom of the ziplock bag was not melted, but starting to seriously pucker and thin.

Additional experiments with better test setup will be performed as soon as we can find a microwave withan external temp probe and more of the decontamination fluid.

Limitations noted include no definitive known innoculants on the mask. No in situ temperature measurement with internal probe or humidity measurement. Need to use a heavier guage plastic heating bag or per the papers in references a dedicated microwave steaming bag. Insufficient decontamination and sterilzation fluid to repeat the experiment for statistical rigor.

…

:star::star::star:Draft Procedure :star::star::star:

Home Sterilization of N95 type conformal fitted face respirators.

You can’t just keep wearing the face respirators without real fear of introducing contamination by either touching the surface or inadvertantly placing the masks on a clean surface contaminating your house or office. Recent data has shown SARS CoV2 remains on cloth for 2 days and surgical masks for up to 7 days.

Research has shown Microwave Generated Steam (MSG) is effective in mask decontamination. From the CDC, " The microwaves produced by a “home-type” microwave oven (2.45 GHz) completely inactivate bacterial cultures, mycobacteria, viruses, and G. spores within 60 seconds to 5 minutes depending on the challenge organism.

Another study confirmed these resuIts but also found that higher power microwaves in the presence of water may be needed for sterilization.

Complete destruction of Mycobacterium bovis was obtained with 4 minutes of microwave exposure (600W, 2450 MHz)"

“Moist heat, consisting of 60°C and 80% RH caused minimal degradation in the filtration and fit performance of the tested FFRs [3, 9, 10]. Heimbuch et al. disinfected FFRs contaminated with H1N1 using moist heat, of 65°C and 85% RH, and achieved a minimal of 99.99% reduction in virus [14]. One limitation of the moist heat method is the uncertainty of the disinfection efficacy for various pathogens”

"Steam treatment and liquid hydrogen peroxide are promising methods with some limitations

"Decontaminate six FFR models and achieved 99.9% inactivation of MS2 bacteriophage. Filtration performance of all tested FFRs scored above NIOSH certification requirements. Three FFRs were further evaluated for three cycles of steam exposure and demonstrated no change in filtration performance [15]. Bergman et al. also demonstrated acceptable filtration performance after three cycles of exposure to microwave generated steam [3]. Microwave generated steam had little effect on FFR fit after exposure to up to three cycles of steam [9, 10].

Using microwaves to produce steam to decontaminate FFRs is not without limitations. Not all microwaves are constructed the same and some are more powerful than others. The effect of higher power microwaves on FFRs is unknown. Furthermore, the metal nosebands of FFRs may cause arcing, sparks inside the microwave oven, during exposure to microwaves."

From remarks on “Put disposable N95 masks in microwave kill coronavirus resuse” blog by the physician, “As per earlier comment, if N95 has metal strip, microwave for 30 seconds, wait 30 to 45 seconds, microwave for 30 seconds, etc… Let the metal cool down. Best to repeat 4 – 5 times with cool down each time. One mask at a time only is what doctor stated.” TBD.

“To date, there’s little research on microwaving Covid-19. However research on human parainfluenza – an RNA virus just like Covid-19 – has been done. These scientists from the Department of Microbiology at Oklahoma State University concluded that running a microwave on high for 3 minutes was enough to disinfect plastic petri dishes.Microwaving parainfluenza for 3 minutes kills virus”.

"Reusing filtering facepiece respirators (FFRs) has been suggested as a strategy to conserve available supplies for home and healthcare environments during an influenza pandemic.

For reuse to be possible, used FFRs must be decontaminated before redonning to reduce the risk of virus transmission; however, there are no approved methods for FFR decontamination. An effective method must reduce the microbial threat, maintain the function of the FFR, and present no residual chemical hazard. The method should be readily available, inexpensive and easily implemented by healthcare workers and the general public. Many of the general decontamination protocols used in healthcare and home settings are unable to address all of the desired qualities of an efficient FFR decontamination protocol.

The goal of this study was to evaluate the use of two commercially available steam bags, marketed to the public for disinfecting infant feeding equipment, for FFR decontamination.

The FFRs were decontaminated with microwave generated steam following the manufacturers’ instructions then evaluated for water absorption and filtration efficiency for up to three steam exposures. Water absorption of the FFR was found to be model specific as FFRs constructed with hydrophilic materials absorbed more water. The steam had little effect on FFR performance as filtration efficiency of the treated FFRs remained above 95%.

The decontamination efficacy of the steam bag was assessed using bacteriophage MS2 as a surrogate for a pathogenic virus. The tested steam bags were found to be 99.9% effective for inactivating MS2 on FFRs; however, more research is required to determine the effectiveness against respiratory pathogens."

My experiment to disinfect respirator masks…will let you know!

YOU MUST REMOVE THE METAL STRIP!

  1. Wash
  2. Gloves
  3. Remove Mask by strings and deposit on disposable paper toweling or paper.
  4. Cut slot at top of mask and Remove Metal strip using tweezers or needle nose pliers
  5. Wrap mask with heavily moistened paper towel to generate consistent steam heating of mask surface
  6. Place in Paper Sack to prevent contamination of Microwave surfaces and contain steam
  7. Nuke per CDC instructions. Goal is 68 C at 85%RH for several minutes
  8. Wash and Change Gloves
  9. Recover Nuked Respirator Mask to “clean” paper towel and dispose of moist HOT towel in covered sanitary waste bag
  10. Reinsert 70% alchohol or 0.05% bleach sanitized metal strip
  11. Allow to dry
  12. Seal mask in disposable plastic Bag Respirator for “2??” days
  13. Wipe down microwave surface with approved virucide.
  14. Cycle respirator back into service on third day.
  15. Be aware of cross contamination in handling exposed mask surfaces…

https://www.google.com/amp/s/boomers-daily.com/2020/03/20/health-put-disposable-n95-masks-in-microwave-kill-coronavirus-resuse/amp/

65

:star::star:Preliminary Nuke the Mask Experiment :star::star:

Okay Mr. Wizard what was the result of your experiment.

“Help me, Mr. Wizard, I don’t want to be Contaminated any more!”

“Drizzle, Drazzle, Druzzle, Drome; time for this one to come home.”
…

Hypothesis: Disposable medical and surgical masks could be effectively steamed in an home microwave oven to reuse.

Objective: Safely steam heat different types of nonwoven fiber, cloth, and paper mask to sufficient heat with steam per prescribed CDC references. Achieve 160°F(71C) for 3 to 5 minutes without melting the plastic bag or destroying mask while saturating with steam. Secondary objectives were to not destroy the microwave, start a fire, contaminate the entire kitchen, or get thrown out of the house.

Method: Nuke the crap out of current N95 and Non N95 masks in a 1,000 Watt Microwave Oven (preferrably without destroying it or otherwise pissing off the missus) while controlling cross contamination.

Materials:

Frigidare 1KW Microwave oven 2450MHz with glass rotating stage @ 3min, 3min 30 sec, 4 min
Great Value Double Zip Quart Storage Bags
Bounty Paper Towels
Tap Water
Surgical Gloves
Needle Nose Pliers
Scotch Magic Tape
Exacto Knife
Tweezers
Kitchen Tongs
GDealer Digital probe thermometer (-50 to 300C)

Discussion:

Masks were carefully inspected and aluminum nose strip removed using Exacto knife and tweezers leaving small slot to reinsert aluminum strips. One resembled a plastic coated wire tie rather versus the flat mallable aluminum strip.

Each mask was flattened and wrapped in a fairly well saturated double thickness paper towel and inserted into the ziplock plastic bag. The mouth of the bag was closed but not zipped to let the steam escape.

Each bag was nuked (irradiated) for 3 to 4 minutes until the digital thermometer indicated 160F. The bag was left in the closed microwave for an additional two three minutes to ensure saturation and apply supplemental internal alcohol disinfectant solution to the experimental staff.

3 minute irradiation seemed to achieve good level of steam and 140° to 150°F temperature. At 3 min 30 sec 160° to 168°F was observed. At 4 minutes in the largest mask the indicated temperature was 198 to 204°F and it maintained above 165°F in the bag for 3 minutes or more. Exact temperature decay data is not clear to to additional prophylactic applications of ethanol decontamination fluid.

Noted is after 5 or more 3 to 4 successive irradiation steam sessions, minor to no puckering of the mask was noted. The bottom of the ziplock bag was not melted, but starting to seriously pucker and thin.

Additional experiments with better test setup will be performed as soon as we can find a microwave withan external temp probe and more of the decontamination fluid.

Limitations noted include no definitive known innoculants on the mask. No in situ temperature measurement with internal probe or humidity measurement. Need to use a heavier guage plastic heating bag or per the papers in references a dedicated microwave steaming bag. Insufficient decontamination and sterilzation fluid to repeat the experiment for statistical rigor.

…

:star::star::star:Draft Procedure :star::star::star:

Home Sterilization of N95 type conformal fitted face respirators.

You can’t just keep wearing the face respirators without real fear of introducing contamination by either touching the surface or inadvertantly placing the masks on a clean surface contaminating your house or office. Recent data has shown SARS CoV2 remains on cloth for 2 days and surgical masks for up to 7 days.

Research has shown Microwave Generated Steam (MSG) is effective in mask decontamination. From the CDC, " The microwaves produced by a “home-type” microwave oven (2.45 GHz) completely inactivate bacterial cultures, mycobacteria, viruses, and G. spores within 60 seconds to 5 minutes depending on the challenge organism.

Another study confirmed these resuIts but also found that higher power microwaves in the presence of water may be needed for sterilization.

Complete destruction of Mycobacterium bovis was obtained with 4 minutes of microwave exposure (600W, 2450 MHz)"

“Moist heat, consisting of 60°C and 80% RH caused minimal degradation in the filtration and fit performance of the tested FFRs [3, 9, 10]. Heimbuch et al. disinfected FFRs contaminated with H1N1 using moist heat, of 65°C and 85% RH, and achieved a minimal of 99.99% reduction in virus [14]. One limitation of the moist heat method is the uncertainty of the disinfection efficacy for various pathogens”

"Steam treatment and liquid hydrogen peroxide are promising methods with some limitations

"Decontaminate six FFR models and achieved 99.9% inactivation of MS2 bacteriophage. Filtration performance of all tested FFRs scored above NIOSH certification requirements. Three FFRs were further evaluated for three cycles of steam exposure and demonstrated no change in filtration performance [15]. Bergman et al. also demonstrated acceptable filtration performance after three cycles of exposure to microwave generated steam [3]. Microwave generated steam had little effect on FFR fit after exposure to up to three cycles of steam [9, 10].

Using microwaves to produce steam to decontaminate FFRs is not without limitations. Not all microwaves are constructed the same and some are more powerful than others. The effect of higher power microwaves on FFRs is unknown. Furthermore, the metal nosebands of FFRs may cause arcing, sparks inside the microwave oven, during exposure to microwaves."

From remarks on “Put disposable N95 masks in microwave kill coronavirus resuse” blog by the physician, “As per earlier comment, if N95 has metal strip, microwave for 30 seconds, wait 30 to 45 seconds, microwave for 30 seconds, etc… Let the metal cool down. Best to repeat 4 – 5 times with cool down each time. One mask at a time only is what doctor stated.” TBD.

“To date, there’s little research on microwaving Covid-19. However research on human parainfluenza – an RNA virus just like Covid-19 – has been done. These scientists from the Department of Microbiology at Oklahoma State University concluded that running a microwave on high for 3 minutes was enough to disinfect plastic petri dishes.Microwaving parainfluenza for 3 minutes kills virus”.

"Reusing filtering facepiece respirators (FFRs) has been suggested as a strategy to conserve available supplies for home and healthcare environments during an influenza pandemic.

For reuse to be possible, used FFRs must be decontaminated before redonning to reduce the risk of virus transmission; however, there are no approved methods for FFR decontamination. An effective method must reduce the microbial threat, maintain the function of the FFR, and present no residual chemical hazard. The method should be readily available, inexpensive and easily implemented by healthcare workers and the general public. Many of the general decontamination protocols used in healthcare and home settings are unable to address all of the desired qualities of an efficient FFR decontamination protocol.

The goal of this study was to evaluate the use of two commercially available steam bags, marketed to the public for disinfecting infant feeding equipment, for FFR decontamination.

The FFRs were decontaminated with microwave generated steam following the manufacturers’ instructions then evaluated for water absorption and filtration efficiency for up to three steam exposures. Water absorption of the FFR was found to be model specific as FFRs constructed with hydrophilic materials absorbed more water. The steam had little effect on FFR performance as filtration efficiency of the treated FFRs remained above 95%.

The decontamination efficacy of the steam bag was assessed using bacteriophage MS2 as a surrogate for a pathogenic virus. The tested steam bags were found to be 99.9% effective for inactivating MS2 on FFRs; however, more research is required to determine the effectiveness against respiratory pathogens."

My experiment to disinfect respirator masks…will let you know!

YOU MUST REMOVE THE METAL STRIP!

  1. Wash
  2. Gloves
  3. Remove Mask by strings and deposit on disposable paper toweling or paper.
  4. Cut slot at top of mask and Remove Metal strip using tweezers or needle nose pliers
  5. Wrap mask with heavily moistened paper towel to generate consistent steam heating of mask surface
  6. Place in Paper Sack to prevent contamination of Microwave surfaces and contain steam
  7. Nuke per CDC instructions. Goal is 68 C at 85%RH for several minutes
  8. Wash and Change Gloves
  9. Recover Nuked Respirator Mask to “clean” paper towel and dispose of moist HOT towel in covered sanitary waste bag
  10. Reinsert 70% alchohol or 0.05% bleach sanitized metal strip
  11. Allow to dry
  12. Seal mask in disposable plastic Bag Respirator for “2??” days
  13. Wipe down microwave surface with approved virucide.
  14. Cycle respirator back into service on third day.
  15. Be aware of cross contamination in handling exposed mask surfaces…

https://www.google.com/amp/s/boomers-daily.com/2020/03/20/health-put-disposable-n95-masks-in-microwave-kill-coronavirus-resuse/amp/

66

Health-related quality of life in patients with immune mediated inflammatory diseases: A cross-sectional, multidisciplinary study

JuliaSpierings, et.al.

67

CDC Napkin Facecloth

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover.html

68

Preprints in Review. from WebMD

Susceptibility of ferrets, cats, dogs, and different domestic animals to SARS-coronavirus-2

April 3, 2020 – As scientists race to learn more about COVID-19, several new studies suggest that the coronavirus that causes the disease can also infect pets, particularly cats and ferrets.

One study experimentally infected a wide range of domestic animals with coronavirus and found that cats and ferrets can be infected with the virus and pass it other animals, too. The same study found pigs, chickens and ducks couldn’t be infected, so that’s good news.

Another study checked the blood of more than 100 cats in Wuhan, China, to see if they had developed immune weapons against the virus, indicating that they’d fought off an infection. About 1 in 10 cats tested in the study had neutralizing antibodies to coronavirus, indicating they’d recovered from an infection.

A third study experimentally infected ferrets and found they got sick, with fevers, fatigue and coughs. They also shed live virus, which infected other ferrets.
The studies are pre-prints, which means the research hasn’t yet been peer reviewed, so the results are not the final word. But,they follow reports by health officials in Hong Kong of the cases of two dogs that became infected with the virus that causes COVID-19—a German shepherd and a Pomeranian.

  1. Susceptibility of ferrets, cats, dogs, and different domestic animals to SARS-coronavirus-2
    Hualan Chen doi: https://doi.org/10.1101/2020.03.30.015347
    Susceptibility of ferrets, cats, dogs, and different domestic animals to SARS-coronavirus-2 | bioRxiv

  2. SARS-CoV-2 neutralizing serum antibodies in cats:a serological investigation Qiang Zhang1†, Huajun Zhang
    https://www.biorxiv.org/content/10.1101/2020.04.01.021196v1.full.pdf

  3. Infection and Rapid Transmission of SARS-CoV-2 in Ferrets https://www.cell.com/pb-assets/journals/research/cell-host-microbe/PDFs/chom_2285_preproof.pdf

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An interesting update on studies related to Blood Pressure Meds and Covid 19

https://www.mdlinx.com/allergy-immunology/top-medical-news/article/2020/04/03/7644293/

70

Stability of SARS Coronavirus in Human Specimens and Environment and Its Sensitivity to Heating and UV Irradiation (SARS CoV 1)
September 2003

The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4 degrees C, at room temperature (20 degrees C) and at 37 degrees C for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees C, at 67 degrees C and at 75 degrees C, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.

https://www.researchgate.net/profile/Xiao_Ping_Dong/publication/8995908_Stability_of_SARS_Coronavirus_in_Human_Specimens_and_Environment_and_Its_Sensitivity_to_Heating_and_UV_Irradiation/links/5e2fa67f299bf10a6598fa29/Stability-of-SARS-Coronavirus-in-Human-Specimens-and-Environment-and-Its-Sensitivity-to-Heating-and-UV-Irradiation.pdf

71
72

Good numbers starting to turn out on new hospitalizations. 2 to 3 weeks of people not breathing in each others face and washing their hands is showing. No magic, just science…What we do today shows up 21 days later. Like new habits. Good job people, well at least most of us.

73

Just because your wearing a mask doesn’t mean your NOT going to contaminate something if your sick.

I DOES slow the VELOCITY and therefore the DISTANCE you spread the pathogen.

Viral contamination at 20cm (8 inches) was reduced by only roughly 1/2 to 1/3 respectively for a surgical mask and cotton mask.

Wear your mask but it doesn’t make you Batman or Superman.

While not completely eliminating, it will reduce droplet fraction by a minimum of 50 to 60%, thereby significantly reducing subsequent fomite secondary transmission from post deposition aerosolization.

N95 masks weren’t tested nor were vented masks.

…

“We compared disposable surgical masks (180 mm × 90 mm, 3 layers [inner surface mixed with polypropylene and polyethylene, polypropylene filter, and polypropylene outer surface], pleated, bulk packaged in cardboard; KM Dental Mask, KM Healthcare Corp) with reusable 100% cotton masks (160 mm × 135 mm, 2 layers, individually packaged in plastic; Seoulsa).”

"A petri dish (90 mm × 15 mm) containing 1 mL of viral transport media (sterile phosphate-buffered saline with bovine serum albumin, 0.1%; penicillin, 10 000 U/mL; streptomycin, 10 mg; and amphotericin B, 25 µg) was placed approximately 20 cm from the patients’ mouths.

Patients were instructed to cough 5 times each onto a petri dish while wearing the following sequence of masks: no mask, surgical mask, cotton mask, and again with no mask. A separate petri dish was used for each of the 5 coughing episodes. Mask surfaces were swabbed with aseptic Dacron swabs in the following sequence: outer surface of surgical mask, inner surface of surgical mask, outer surface of cotton mask, and inner surface of cotton mask."

“This experiment did not include N95 masks and does not reflect the actual transmission of infection from patients with COVID-19 wearing different types of masks. We do not know whether masks shorten the travel distance of droplets during coughing. Further study is needed to recommend whether face masks decrease transmission of virus from asymptomatic individuals or those with suspected COVID-19 who are not coughing.”

…

"was placed approximately 20 cm (8 inches) from the patients’ mouths. Patients were instructed to cough 5 times each onto a petri dish while wearing the following sequence of masks: no mask, surgical mask, cotton mask, and again with no mask. A separate petri dish was used for each of the 5 coughing episodes. "

The mask still does its job by significantly reducing the velocity of propagation of any large droplet through the mask.

Since the ones tested were polypropylene inner layer, the mean free path of travel, is maximized, and the “ping pong ball making it’s way through forest of pick up sticks” analogy abides.

Collisional momentum transfer, adsorption, and electrostatic attraction are the principal methods of stopping slowing micron and submicrin scale particles.

Mucite expression contain dissolved salts which, when dried, increases the polar moment that helps defeat the lipid envelope of most viral particles.

External contamination is still a concern for to to 48 hours and microwave generated steam 60C for 4 to 5 minutes is recommended by various CDC referenced authors for decontamination.

74

Wee Corona Beasties Too!