Sylvia Mitchell | Why should you wear a mask

My job requires me to work in a laminar flow which has a HEPA filter that filters out 99.97% of particles 0.3 microns in size; this includes bacteria, fungi and viruses. Even one microbe on a Petri dish can grow and over-ride an explant in a few hours. The HEPA filter prevents this. This experience got me to musing about the present situation and the insufficient guidance being given, which led me to write this article.

The new coronavirus which causes COVID-19 is about 0.125 microns wide. A micron is 0.001 mm. As reference, human hair is between 17-181 microns wide. This virus remains infective in large or small droplets from a cough, sneezing, talking or just breathing, which can be blown quite far from an infected person, who may or may not have visible symptoms. The large droplets are 5-10 microns wide and fall towards the earth quickly. The smaller droplets stay in the air longer and can float longer distances. Coughing, singing, or even raising one’s voice to be heard can cause these small droplets to travel further than the recommended 6 feet. This new virus can remain viable for several hours in these small droplets. We are fighting a virus that spreads easily.

Think about this: if you sneeze into your elbow and then offer the elbow instead of your hand as a way of greeting, what do you think will happen? When you accept change in the bus, the virus could be on the money. So what should you do? Accept it into a plastic bag and spray with 70% alcohol and wait a couple of hours before adding it to your purse.

We are asked to wear masks, but do we understand why, how, when, and what?

Why wear a mask?

There are two reasons for wearing a mask

1. To protect the wearer from getting infected. In order to protect the wearer, any virus containing droplets must be prevented from getting under the mask. Contamination usually falls down (not up), so the top of the mask must fit snugly. A disposable paper sun hat worn over the mask should be considered. A cap is always useful. A plastic visor with a rubber across the forehead is even better. This will help prevent particles falling out of the air from easily getting under the mask. The sides of the mask should extend close to the ears, and fit snugly to prevent air entering at the sides. The N95 mask fits closer to the face, so is more effective, but needs to fit snugly to provide the best protection. After taking off the mask, wash the entire face with soap and water.

2. To protect others from being infected by the wearer. If the wearer is coughing or sneezing and has to go out, the face mask will reduce the number of particles the wearer releases, and can help protect other people from becoming sick. However, a mask is not foolproof. So it is best to inform the authorities and self-isolate if you have symptoms. With the new coronavirus, it is noticed that, before symptoms are obvious, such a person can still spread the virus. So in this case, a mask will help. It is best not to depend on it, however, and you should still carry out physical distancing as if you were not wearing a mask.

What we need to encourage is physical distancing NOT social distancing. We have many methods that allow us to socialise without physical contact. What we need now is to be physically distant from each other. In order to allow family units to be safe to touch, my suggestion would be to designate one person to go out and come in. That person would follow a regime that would include:

• Going out: Pray a covering over you in Jesus name, put on a clean mask properly (see below), go to the closest outlet and get just what you need while staying far from anyone, receive change as outlined above, then get home.

• Coming in: Take off mask (see below) – either dispose into garbage bag or into a pre-arranged bucket with soapy, bleach water. Wash hands and face with soap and water. Bathe immediately.

If the designated person starts coughing or sneezing, they need to self-isolate and the authorities be called. Another person should then be designated to take over the task.

Why do we wash our hands?

Viruses are not alive. Viruses cannot multiply on their own. This virus is a piece of RNA surrounded by a lipid membrane with protein spikes. They cannot reproduce without using the cellular machinery of a living host. So they will never multiply on your hands, they can only multiply inside cells. The infectious particle remains on your hands until you wash it off. It does not remain “infectious” forever, though. On a surface, it might remain infective for a couple of days. It will not wash off unless you wash your hands, and there is a very, very high chance you will transfer infectious particles from your hand to your eyes, nose, or mouth, if you do not wash your hands. Also, you can transfer virus particles to doorknobs, keyboards, telephones, etc. Hence, wash your hands. Most people touch their face multiple times per hour without even realising it. That is how the virus gets into a body. The other way, of course, is breathing a virus from a sick person. But most community spread is due to people before they know they are sick.

How to wear a mask?

To put on the mask, determine which way is up. The metal strip is to be pressed to the nose to get a close fit. The style of the mask should fit the shape of the nose such that there is no space around the top of the nose for air to get it. Remember, contaminated air drops down, not up, except in eddies. Wearing a cap reduces downward movement of contaminated air. If there is no metal strip on the mask, it must still fit smugly over the nose to be of any use. The sides of the mask should also be close-fitted. Wash hands with soap and water before removing a mask from its container. For reusable masks, after washing and drying, store in plastic until use. Wear the mask even when talking to someone, even the media or pertinent officials, to reduce spread.

To remove the mask, avoid touching the front of the mask. Only touch the strings of the mask when removing. Don’t shake the mask. Drop the mask into a plastic bag at the entrance of the house. Do not carry or shake the removed mask around the house. If reusable, put the mask into a pre-arranged container with soapy, bleach water at the entrance of the house. Wash out thoroughly and hang to dry. Do not reuse the cloth mask if it gets stretched.

When to wear a mask?

• When leaving the house to go shopping etc, wear a mask.

• When talking with the media people, talk through the mask. Taking it off to talk exposes the media personnel and others nearby, if you are infected or if the virus is on the mask.

• Do not pull down the mask or remove the mask until you reach home because, if you push it down to talk, the virus particle, if there, can become airborne and enter your mouth as you talk.

• If you are sneezing and coughing and have to go out in an emergency, wear a mask.

What mask to wear?

Are all masks the same? The answer is no, the mask with the highest pore size requires the wearer to maintain a greater physical distance than one wearing a mask with a smaller pore size.

• A HEPA filter prevents 99.97% particles of 0.3 microns. A HEPA filter can also be found in air filters for the house, but are not widely available in masks.

• An N100 mask would prevent 100% of particles of 0.3 microns. There are not many of these around, and they are very expensive.

• An N95 mask prevents 95% of particles of 0.3 microns.

• A surgical mask. This mask was made to protect the patient from the surgeon. Not the surgeon from the patient.

• A dust mask. This was made to keep out dust, not virus particles.

• A cloth mask with three layers sewn in

• A cloth handkerchief

Use the highest grade possible. Wear with a cap or disposable paper sun hat or plastic visor if available.

How to test the efficiency of your mask? A simple method suggested to me is that, if you can blow out a lighter flame through the mask, then it is of not much use. Also, if you can smell smoke through the mask, the pore size is too large to stop this virus. We don’t want to wear a mask that makes us feel safe when we are not.

If we can do this for at least 14 days after the last person gets infected, this virus can be beaten!

Dr Sylvia Mitchell is senior lecturer and head of Medicinal Plant Research Group at The Biotechnology Centre at The University of the West Indies, Mona. Email her at sylvia.mitchell@uwimona.edu.jm or sylviamitchell.biotech@gmail.com.