04/02/2020
Clear information about COVID-19 Contagion and how to stay safe; from a medical source
Marty Teltscher
15 hrs
We have all heard of various jurisdictions, some of which have previously advocated using bandanas (?!), now recommending universal masking, even for general Public, and even for outdoors. This is illogical on many levels, will deplete what limited mask stores that are left, and result in deaths of sick patients because Healthcare workers won’t be able to administer care (nor should they be expected to if they cannot be properly protected), and sicken altruistic healthcare workers. I’ve received many questions about this today in particular.
From what we know, and ongoing experience, the natural act of coughing produces droplets of various sizes. In the general public, outdoors, or large rooms such as a large store - the very small number of aerosolized droplets produced and the physical properties of this virus does not permit it to remain suspended in air for a long enough time or in a concentration (infective dose) that may allow for infection.
The overwhelming majority of virus that emerges from people’s face are in large droplets that will fall to the ground by gravity. On the way to the ground they often impact on objects, tables, hands, etc. These inanimate contaminated objects capable of transmitting infections are called fomites. Once you contact a fomite, and if there is large virus in a significant infective dose, and bring your contaminated hands in contact with mucosal surfaces - in particular the interior nose - an infection can take hold.
There is always a theoretical risk that you run into a “ballistic droplet” - a infectious droplet that has defied probability and landed on your mucous membranes (eyes, nose, mouth) but this occurrence is exceedingly improbable. For most comparable levels of risk, most people would usually not even give the situation a consideration (not even me, and I’m the most ultra conservative risk taker you’ll find).
With this explanation the following should be clear:
(1) you do not need an N95 mask unless you are a healthcare worker attending to a critically ill patient or performing one of many aerosol generating medical procedures (AGMP). These are situations where there is a significantly increase probability of inhaling an infective dose of fine infectious particles and where a high efficiency filtering mask is important.
(2) in the general public, you are far more at risk of contracting the disease by fomites and contaminated hands than encountering an infectious dose of aerosol. So you are much better off not wearing mask or gloves since you will naturally bring your hands to your face to adjust your mask, and/or contaminate your hands by touching the front of your mask, and/or not wash your hands because you are wearing (dirty filthy infected) gloves.
(3) I cannot argue that a procedural mask will create a barrier for those that can’t control themselves and must pick their nose or put their fingers in their mouths for whatever reason. But that’s where it starts and ends. If you have a compulsion, you do not need a mask, you need a lifestyle coach. You are better off washing your hands +++, and not touching your face at all.
When I sit in my office in COVID-19 central (formerly the JGH) in Montreal I DO NOT wear a mask. When I walk around the hospital almost always on the way to see a patient (because I have little reason to walk around otherwise) I do wear a procedural mask because of the potential viral burden in our hospital - in particular of encountering fomites, contaminated patient environnements, or getting within 2m of an asymptomatic shedding nonCOVID patient (or HCW) and accidentally contacting my face with potentially highly contaminated hands (both of which have been washed so frequently that they no longer have epidermis). It is mentally fatiguing to constantly be thinking about not adjusting my mask, and wash wash wash hands, and not touch my face. N95 remains reserved for the situations identified above.
(4) engineering studies using simulated coughs, sneezes, or PCR of air samples do not necessarily replicate the natural transmission dynamics or biology of the virus. The information obtained is contributory, but in real life to date, this virus still follows droplet-contact transmission dynamics. So for those of you holding out hope - you can’t use these studies to keep your wife 8m away instead of 2m away.
(5) graphs showing bending curves in Asian countries compared to non Asian countries can not be attributed ONLY to a universal masking policy, much in the same way that it can’t be attributed to eating more rice, singing more karaoke, or stating your personal name last and your family name first. Societal norms, the intensity of what is acceptable social distancing, and severity of enforcement also factor into this. Want to find out enforcement? Spit out your gum on a sidewalk in Singapour. Ain’t no sneaking around a Cote Saint Luc Mikva in Singapour. There is also extremely aggressive testing and identification of cases such as South Korea, and misreporting such as China.
Wash your hands. Cough and sneeze into elbows. Keep fingers out of face holes. Wipe down your groceries. Wash hands when you get home. Wash hands before eating. And keep apart. Unless you plan on laying on the ground in Cavendish mall face up, you will not even need a procedural mask.
And wash your hands.
