Thursday, November 17, 2022

Science of Mask Efficiency

A thread from Dr. Leo Lam, who has a Ph.D. in Electrical Engineering, worked for over twenty years as a science advocate, and was co-founder of medical imaging software.

I'm tired of hearing the contrarians talking about how masks don't work as protective devices against respiratory diseases as our nation's pediatric hospitals are full of children sick with RSV/Flu and COVID continues to be the 3rd leading cause of death. The contrarians are WRONG. Some of them are already making attempts to take apart the excellent study done at the Boston School District with minor technicalities while ignoring a fundamental fact: the study is only a proxy. 

These contrarian physicians mistakenly believe that RCTs [randomized control trials] or observation of the secondary effects somehow make the gold standard for scientific evidence. It is NOT. Why? Because masks are mechanical devices that are physically measurable. And we have physical data. RCTs, by definition, are examining efficacy by proxy because the effect of drugs (and some medical devices) is not directly observable. You can't directly see how the chemicals interact with our cells/molecules or organs until we have nanobots with viewing capabilities. With masks, we can directly test and measure their efficacy via controlled particulate generators and sensors. This is the same for other physical objects, like seat belts, parachutes, and helmets. It would be absurd to run RCTs on them. Unethical, too. 

Some may argue that lab testing does not equal real-world results. That is false. If one looks into the OSHA/NIOSH testing protocol, one would realize how much thought were put into the design of these protocols to simulate real-world environments. If you ask scientists and engineers who work in cleanrooms (like myself), they would clearly show you that the mask testing mirror real-world results; if not, our semiconductor manufacturing industry would collapse. 

With that established, what did physical testing with rigorous standards tell us? Masks work. Masks work very well. And fortunately for us, they work specifically well with COVID-19-containing particles in the single-digit micron range, with an N95 achieving 98.4% filtration efficiency. Even a surgical mask with ties has 71.5% efficiency. The results mirror CDC's study on mask effectiveness using "testing positive for COVID-19" as an endpoint. It is no surprise to all of us, physical scientists. 

Physical testing allows us to go even further. We can even establish whether filtering efficiency goes down for those single-use surgical masks after multiple usage, saving precious resources during tough times. For more studies that are all done by proxy on masks' efficacy, check out this thread by @DrCanuckMD

Our pediatric hospitals are full. Many children are sick and as a civilized society we, as adults, must do our part to protect them. Masks are the most effective tool to guard against respiratory diseases.They work exceptionally well and so far, the claim for the negative impacts is flimsy at best. Those claims won't even pass the contrarians' own scrutiny if they bother to use the same standard. It only shows that it has never been about efficacy, it's ideology. To those contrarians who insist on RCTs, I challenge them to develop a protocol for a mask RCT, the results of which THEY would accept. I challenge them to allow the scientific community to scrutinize this protocol. Otherwise, they are just complaining without substance. I am fairly confident that this protocol would not pass any IRB scrutiny. For now, please, wear a mask to protect yourself and others during this triple pandemic.  

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