Mask reuse in home setting?

[jmcmurry]

Mask question from someon: "I'm in isolation w/in isolation, separated at home from my mildly symptomatic family while we await test results. We have just a few masks. If virus can only survive for a certain time, can I re-use mask after several days, disinfecting the little metal strip?"

c/o https://twitter.com/JeffSharlet/status/1239641846613147651

Need someone to +1 this

[steesdale]

We should pull best practices for mask use and reuse for different types, and what the tradeoffs are to help people make good decisions. A few topics to consider...

• How to take on / off masks - dont touch outside
• Where to store masks that you are reusing (away from kids, pets, traffic, etc..)
• How to fit and size masks - this is hard when not trained
• What surgical masks are good for (Sick People)
• Not to hoard N95 masks - health providers need these.

[mattbell]

Here's some research I did on mask reuse:

From: https://www.facebook.com/thismattbell/posts/10159622229081038

Since mask supply is limited, there are questions about mask reuse. There are conflicting reports about whether it is safe to sterilize and reuse masks. [1] [4] Almost everyone recommends discarding masks once used in a high-risk setting (eg a hospital, or contact with a person with COVID-19). However, reuse after low-risk use may be possible. Some sources claim that improvised fabric or surgical masks can be sterilized in boiling water and then dried, disinfected with UVC light, or left out in the sunlight for several days. [0] [1] N95 masks need to stay dry. An old study from SARS-CoV suggests that temperatures of 60C / 140F for 30 minutes will destroy a different coronavirus. [2] There is no analogous study for this coronavirus yet, but it’s likely its temperature tolerance is similar. N95 masks appear to only mildly be damaged by this level of heat. [3] Thus, it’s possible you could “bake” your used N95 masks at low heat in the oven (eg 180F) to sterilize them without damaging them. I’ve tested this on the 3M brand N95 masks we have and it appears to work.

The case for masks [0] https://www.inkstonenews.com/health/coronavirus-health-researchers-urge-global-authorities-consider-broadening-use-face-masks/article/3074453 

Washing surgical masks: [1] https://focustaiwan.tw/society/202002020012 

Heat for inactivation of the original SARS coronavirus: [2] https://www.ncbi.nlm.nih.gov/pubmed/15118911 

Mask safety during sanitization [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781738/ 

Claims of mask steaming as ineffective:[4] https://factcheck.afp.com/novel-coronavirus-health-experts-warn-against-steaming-face-masks-reuse-after-misinformation-chinese

[jmcmurry]

Possibility of fomite transmission can't be ignored, especially now. 3 days would be the lowest limit I am comfortable recommending. 9 days, see https://github.com/flattenthecurve/guide/issues/34

[jmcmurry]

One thing that the Lancet article doesn't directly address is the issue of mask destigmatization. If the messaging is that only sick people should wear masks, the assumption will be that people wearing masks are sick and vulnerable to prejudice. By normalizing (home-made) mask use amongst the "walking well", we could improve outcomes for everyone, not only because those who are symptomatic will feel free to use them, but also because asymptomatic transmission is clearly such a big problem.

[mattbell]

I spent a lot of time researching mask reuse. I put this Medium post up yesterday, and it has a significant section on mask reuse: https://medium.com/@llebttam_45762/masks-work-wear-them-b450ac9f3b7d

I'd be happy to turn any portion of this into a post for flattenthecurve if you'd like. Just let me know the scope and length and I can make it happen.

[paul-hammant]

US health services group "Deaconess Health Systems" shares a mask design PDF and Youtube Video - Mar 20, 2020

US health services group Providence shares a mask design video - Mar 21, 2020 (part of their 100 million mask initiative)

[paul-hammant]

A 2019 study on masks: Modeling the Effectiveness of Respiratory Protective Devices in Reducing Influenza Outbreak (Listed on the USA's "National Center for Biotechnology Information" site)

From that study's "Results" section: The level of compliance was assumed to be the same for the susceptible and infected populations. [...] A 20% compliance rate [of surgical or better masks] cuts the infection prevalence roughly in half and delays the peak of the epidemic to around day 25. For 50% compliance [of surgical or better masks] reduce the prevalence to less than about 5%. At 80% compliance, the infection prevalence is negligible where the maximum is roughly 5%.

Anyone still think that FlattenTheCurve.com should not move to "masks work" language? Qualified as surgical masks != N95 masks != cloth or home made masks.