Friday, July 17, 2020

The Next COVID Mantra: #WearMasksSaveLIVES

Do a quick internet search on the subject of mask wearing as a measure to reduce the spread of COVID-19 and what you will find will depend on the date the article was printed. There is a marked change of course in the middle of April when the expert advice abruptly shifted from the message that there is no reliable medical evidence supporting the wearing of face masks to prevent transmission of SARS-CoV-2, to the universal recommendations that all wear face masks (facial coverings of any sort) as a measure that could protect others from asymptomatic spread based on emerging data about the asymptomatic spread of SARS-CoV-2. The validity of viral spread as a primary reason for this shift in health policy is seriously undermined by the lack of scientific evidence (which you have to dig deeper to find) and makes it far more likely that these recommendation are largely social in nature.

I've spent a great deal of time (I've got a lot of that these days) researching the science behind viral transmission, what is known or believed about how SARS-CoV-2 is transmitted, and what the established science is on face coverings for the prevention of viral spread. It's been a good course of study for me and I've learned a lot about a subject I knew very little about in March when I rarely concerned myself with getting sick.

I'm not at all a germaphobe. I'm one of those, "what doesn't kill you makes you stronger," kind of moms. I rarely use antibacterial products and short of a good hot water and soap cleaning I'm not a fan of harsh chemicals as a regular cleaning product. I've not worried about my kids getting sick because their dog licked them in the mouth or because they played in the mud. I never quite understood my "mom friends" who would call to inform me their child had a cold before we got together for a play date. It's just a cold after all.

Needless to say, the pure panic over the pandemic has seemed like a major over-reaction to me. Still, I get that SARS-CoV-2 is as much as 4 times more deadly than the yearly flu for certain segments of the population and is proving much more contagious and that warrants a unique attention. Though early models predicting millions dead by August were significantly overstated, Dr. Fauci’s predictions of 150,000 to 200,000 COVID deaths by August is likely to be realized. Now that the western world has caused massive economic damage with shutdown and stay at home orders this spring, they can hardly go back to that tact, especially when comparisons between strict and flexible states doesn’t demonstrate a clear connection between strict policies and fewer deaths. States are looking for a new mitigation that might provide some reduction in COVID spread and universal masking is the next go to plan.

Will universal mask wearing effective in reducing COVID spread? Does the science support it?

It is very important that ongoing COVID-19 decision-making relies on science-based data and not placating public perception. Let's take a look at the science. First, scientist are conflicted which is to be expected but that doesn't mean there isn't plenty of science to base decisions on. The WHO and CDC have for years acted upon conclusions that the science doesn’t support the effectiveness of universal masking as a reliable method of reducing viral spread. The most surprising finding I discovered the more I dug into the subject was that even the wearing of surgical masks in medical settings has no bearing on viral spread. The body of research tends to support former conclusion of the WHO and CDC that the universal wearing of cloth or surgical masks will not be effective in reducing the risk of SARS-CoV-2 transmission. However, there is some indication that viral spread could be reduced somewhat when masking is required in targeted areas and situations, and in population dense areas targeting transmission vectors would prove to be rational health policy. Similar to the failures of “one-size-fits-all” shutdown when stay at home order, universal masking orders will prove a useless draconian overreach.

Understanding the efficacy of face masks starts with a basic knowledge of virology:
  • Size makes a difference, and viruses are much smaller than bacteria and range in size from 0.01 micron to 0.3 micron. The SARS CoV-2 virus responsible for COVID-19 infection is 0.1 micron. Cloth masks only filter 5.0+ microns, 50 times larger than COVID. Transmission of viral particles is inevitable despite the wearing of face masks. The extent to which face masks have been found effective, is dependent on the capture of larger expectorated water droplets in close proximity, but viral particles are also dispersed in small droplet and aerosol form from ordinary behaviors.
  • The wearing of dust, cloth, or surgical masks provide no protection from the inhalation of viral particles lingering in the air: "Talking, breathing, coughing, and sneezing create aerosol particles (a suspension of particles in the air) in a range of sizes, with viable infectious organisms present in both small and large particles. Smaller particles (less than 5 ┬Ám) will remain in the air for many minutes or even hours, it is believed that SARS-CoV-2 remains airborne for 3 hours. 
  • Smaller particles are more affected by diffusion than gravity, thus making them more likely to remain airborne. In the absence of air currents, airborne particles will disperse slowly throughout a space. Crowded less ventilated areas become vectors for viral transmission.
  • The lateral aerosol spray from coughing and sneezing is redirected to the edges of a face mask covering. Thus, the practice of coughing or sneezing into the crook of your arm provides a better barrier to dispersal of particles, in both cases both aerosol particles and water droplets will escape, but their will be less lateral projection when using ones arm.
  • Masks may be marginally effective when an infected person is in close proximity to others for extended periods of time (at the very least 5 minutes, with most standards being 15 minutes): Since close proximity and duration of exposure are significant factors in viral spread social distancing in public establishments is most effective in the reduction of viral spread. Wearing masks while briefly brushing by people in a store will provide no distinguishable protection from contracting SARS-CoV-2.
  • Higher doses of infectious particles are more likely to result in infection and disease. Close proximity to people with more severe symptoms in relatively enclosed spaces presents the the greatest risk. Exposure to a dose of more widely dispersed infectious particles in larger well ventilated areas, or from the excretion of asymptomatic persons is unlikely a driver of COVID spread. Thus, People who eventually developed severe symptoms are more likely to transmit the disease to others than are those who had mild symptoms. For this reason the more effective health policies relate to preventing those with symptoms from being in close contact with others.
  • It is suspected but not clear that SARS-CoV-2 can be spread by people before they have symptoms. It’s still an open question whether asymptotic persons are spreading SARS-CoV-2, but it is sound science that asymptotic spread is not a primary driver of COVID exposure. Inhalation of particles near the source is the most important mode of transmission which makes social distancing the most effective measure in preventing viral spread.
*University of Minnesota summary of studies has a detailed explanations of the differences between aerosol and droplet defusing of viral particles and the impact of this spread on viral transmission.



Dr. Lawrence W. Gernon, Professor of Global Health, Global National Security & Policy Insitute, UNM wrote:

"While wearing a mask is an individual’s choice, understanding the level of protection and transmission is key. These masks offer no additional protection to the common-sense public health measures of social distancing, and, most importantly, frequent hand washing. Dust and Cloth face coverings may help keep saliva and mucous generated by the wearer from reaching others and surfaces... They are not respirators and do not offer any respiratory protection for particles less than 100 microns and are only intended for splash protection. Penetration of cloth masks by particles was almost 97% vs. medical masks 44%, and moisture retention may result in increased risk of infection."

Let's talk about whether simple cloth face coverings and masks protect others from the spray of your saliva and mucous and whether that alone provides a reasonable measure of protection to others against viral spread. This is the mantra forming around face mask wearing, "Wear it not to protect yourself but to protect others." Is that true? Well, the science that supports that supposition is weak, Some laboratory studies put the level of self protection at zero but have a wide range for the level of communicable protection, from as low as a 2% increase in communicable protection to 25% for ordinary cloth masks. But don't get too excited about that 25% number, there are Studies of performance in real-world settings that put the more optimistic numbers from in lab studies in serious doubt.


I'm sure you've heard lots of news talking about the influenza pandemic of 1918/19, and heard experts, politicians, and media making comparisons between the COVID-19 pandemic and Spanish flu. Pictures of people during that pandemic wearing their cloth masks are posted all over media stories these days, no doubt to give us the impression that we should also dawn our masks. The problem is, that's not the whole story.

Studies seeking a reason for the failure of cloth masks required for the public in stopping the 1918 influenza pandemic, found that the number of cloth layers needed to achieve acceptable efficiency made them difficult to breathe through and caused leakage around the mask. These studies found no well-designed studies of cloth masks as source control in household or healthcare settings. In sum, given the paucity of information about their performance as source control in real-world settings, along with the extremely low efficiency of cloth masks as filters and their poor fit, there is no evidence to support their use by the public or healthcare workers to control the emission of particles from the wearer.

There is not a sound scientific basis to push policies that require the general public wear face masks and coverings all day at school, work, or when they are out in public in most settings. In spite of that, many respond to this reality by saying, "But what can it hurt? And if it helps even a little, isn't it worth it?" Well, the answer might be that it hurts more than it helps when you consider potential side effects, but that is another essay.

Pandemic Precautions that are Science Supported:

While I have spoken out strongly against the reactions to the pandemic that have shut down the world economy, destroying livelihoods and putting many more lives at risk in a myriad of ways, I have personally followed recommendations for social distancing from people outside my immediate social circle and have been more attentive to hand-washing, not touching my face, and reducing symptoms that might cause coughing or sneezing (such as taking my allergy meds).

The only time I have worn a mask, when I went to the doctor, I was surprised at how often I touched my face and how hard it was to breath, and I only wore my mask for an hour. No wonder I see so many employees in stores struggling to keep them on and keep their hands away from their faces. It's impressed on me what Dr. Fauci said about face mask early on, that a recommendation for wide use of them would most likely lead to more risky behavior and be a hindrance to more effective measures in reducing viral spread. In other words, wearing masks may be a physiological placebo that ends up doing more harm than good.


 

Throughout the pandemic I have supported well reasoned mitigation’s surrounding the most vulnerable and vector points for viral spread. I have not denied the efficacy of canceling large crowded social and sporting events, reducing viral spread at private gatherings that can be augmented or suspended without larger economic impacts, and science based measures such as social distancing, heightened hygiene, and the careful protection of at risk populations. 

As face masks are concerned, if a densely populated city could reduce the communicable spread of SARS-CoV-2 even by 10% over the population by requiring masks in vector points of viral spread such as public transit, airplanes, crowded spaces, and indoor spaces with poor ventilation then it would be a worthwhile effort. 

I oppose universal mask wearing edicts that ignore the science and use the heavy hand of the law to force compliance. Not only are these kinds of laws impractical to enforce they are illogical authoritarian reactions to the pandemic are reordering the relationship between government and citizens, destroying our economy, exploiting deep divisions within our nation’s social fabric, and undermining the public confidence in the institutions and leadership of America.

No comments:

Post a Comment