Looking for a #BetterMask but:
✖️N95s are harder to find than TP in 2020
✖️you can’t afford N95s and your government isn’t making them accessible
✖️your workplace mandates medical masks and doesn’t allow N95s
✖️your school gives students medical masks
This 🧵‘s for you
1/
Ensure your medical mask is ASTM graded and is at least a grade 2 mask, preferably grade 3 (will ensure better filtration performance of the mask material)
Important to note, ASTM 3 does not imply or guarantee respirator-quality filtration performance.
2/
For kids and those with smaller faces, try the #KnotTuckTape
Turn that rectangle into something more face-shaped. I think taping the corners is important otherwise the tucked in edges often unfold fairly quickly.
3/
The #KnotTuckTape makes the mask a bit small for my face, but did pass my DIY nebulized bitrex fit test with quiet breathing
With talking and movement it started to slip around and failed.
Still much better than unmodified surgical mask, which failed within seconds
4/
To the experts insisting “N95s are useless if not fit-tested”
Have you ever tried to fit test a “well-fit surgical mask” or “3 layered well-fit cloth mask”?
TLDR they are inferior.
A brief case series and 🧵
1/15
There are two type of fit tests, 1) quantitative fit testing - a portacount machine measures the concentration of aerosol outside the mask versus inside the mask and 2) qualitative fit testing - a potent bitter or sweet aerosolized solution is inhaled under a hood
2/15
I underwent quantitative fit testing on a surgical mask, suboptimally fit KN95 and well fit CN99 (FFP3). The results were intuitive. The surgical mask, while still offering some protection, performed the worst.
When the science and our understanding evolves, it’s important to communicate this clearly and concisely to the public rather than fall back on nuance and shades of gray. Even when this means admitting that previous messaging was incorrect.
Side tweet - Probably could have saved some pages by omitting the giant shades of gray diagram - not a difficult concept
I wear an N95 respirator to protect myself, my patients, my colleagues and my family. Blocking inhalation and exhalation of potentially infectious particles just makes sense during a respiratory pandemic. #PerfectFit on the PortaCount #SayNoToSafetyStewardship#FreshAirWeCare
Because a fit factor of 5 (20% leak) - when quietly breathing through a surgical mask - isn’t respiratory protection. #BewareOfMaskNostrils #BYOPPE
My mask solution earlier in pandemic was a mask brace to optimize my fit. Have since switched to N95s to optimize filtration (respirator material meets higher testing standards) and function (N95 easier to put on, more comfortable, more breathable). #MacGyverYourMask
“During the great COVID pandemic of 2020, you may be shocked to learn that many international ID experts believed that respiratory viruses spread primarily through fomites and eyes, rather than the more obvious route - inhalation...”
“As the pandemic swept across the globe, and cases grew, so did the evidence supporting aerosol transmission. The increased risk in shared indoor air and poorly ventilated spaces and decreased risk outdoors was plain for all to see.”
“The paradigm shift was accepted swiftly by some. Others held firm. Some even postulated that the decreased risk outdoors was related to a mysterious germicidal substance in outdoor air, rather than the obvious answer- dilution.”
Current IPAC policies are heavily weighted towards preventing droplet/fomites spread and active nosocomial outbreaks are blamed on HCWs for not tying gowns correctly, other donning/doffing errors, not wearing proper face shield, etc
Number of studies that have successfully cultured Covid from used hospital gowns/gloves/HCW hands/face shields? 0️⃣
Number that have found SARS-CoV-2 RNA on these items? 0️⃣
Only positive RNA sample on “PPE” was 1 sample on the front of 1 shoe...