So we are many months into a pandemic and people are tired and stressed out and so many are worried about the future. It has been my experience that one of the best ways to decrease worry is to take action. So I have some action steps that we can all take to help relieve worry right now. I will be sharing these in a series of blog posts.
The Great Mask Debate
Protect yourself with a mask and social distancing whenever possible. There has been much controversy surrounding mask wearing. The purpose of wearing masks is to reduce the spread of infection through droplets and aerosols as these particles can contain infectious materials. Droplets and aerosols are naturally produced by the respiratory system and are released from our mouths and noses whenever we breathe, cough, sneeze, talk or sing. We know this because as children we were taught to cover our mouth and nose when we cough or sneeze. The droplets are heavier and are pulled down by gravity which is why distancing can be helpful. Aerosols (very small particles) float in the air for a period up to several hours and spread like smoke through a closed space.
Aside from fit-tested N95 masks, masks provide limited protection for the wearer because some droplets and aerosols can get around the gaps in the sides of the masks. You might ask yourself why, in light of that information, should anyone bother wearing a mask? Have we all not heard about (perhaps on social media) somebody who always wore a mask and still got sick? Masks are more effective in protecting others by reducing the droplets and aerosols that the wearer releases into the air. If we have widespread mask usage the amount of infectious viral particles being released is greatly reduced. The number of infectious particles is one important aspect in spread of a disease.
Per an article published in October 2020 in the journal Nature, surgical masks and comparably constructed fabric masks reduce aerosol expulsion by about 67% and N95 masks reduce 90% of aerosols expelled. That study goes into much more detail looking at 14 different mask materials and it makes for interesting reading if you are interested.
Masks with a vent and fabric neck gaiters are explicitly not effective and should not be used. The vents allow droplets to exit and the neck gaiters have been shown to increase risk by aerosolizing the droplets (making them into very small and more mobile particles). The clear plastic face shields are really not effective at preventing droplet transmission as the droplets pass right around the shield. I have seen these clear plastic shields mounted on a headband and also advertised as masks with a mask-like shape and having earpieces like glasses to hold it against the face. None of those clear shields are effective.
All this data means that by wearing a mask a potentially-infected individual will release fewer droplets into the surrounding area. That decreases the potential for infecting others. If we have all or nearly all persons wearing masks when out in public and everyone’s droplet release potential is decreased and we’ve significantly decreased the risk of disease transmission. When considering the disease-causing capability of an organism we have to consider the characteristics of the organism, the health of the host and the number of the organisms released. Wearing masks decreases the release of disease-causing organisms. Other articles point out that the size of the holes in masks are much larger than the virus itself. This is also true. Viruses travel in droplets and sometimes in smaller particles called respiratory nuclei. These droplets are larger than the virus itself and so may be trapped by the mask. It is important to practice proper masking protocol which means limit handling of the mask and dispose of the mask (or wash it if it is a fabric mask) after it has been worn for a length of time. Bacteria can certainly collect on the mask so these hygiene measures are important. Masks of any kind must cover the mouth and nose as droplets are released into the air by both mouth and nose and if there is a metal nosepiece it should be bent around the nose for optimal fit. It is unnecessary to wear a mask if you are alone in your vehicle, although I always put mine on if I am in line at the coffee shop drive-through and need to interact with the employees to receive my order. It is not necessary to wear them if you are outside away from others as the droplets you are releasing will be quickly dispersed in the outside air. Indoor ventilation systems allow the droplets and aerosols to linger which is why masking is important indoors. I have read some interesting articles about advances in indoor air quality management which look wonderful so that would be a nice positive development from this challenging situation.
One study that came out in April in the Annals of Internal Medicine purported to show that masking was ineffective. It has since been retracted. Early in the pandemic there were so many unknowns that it is not surprising that some of the early findings were determined to be incomplete or incorrect. Much of the hesitancy for masking recommendations on the part of the WHO and CDC was related to supply issues for healthcare workers. We have learned so much since then and there are masks in fashion patterns and instructions for mask making all over the internet. With these options the depletion of mask supply is no longer a concern. The fitted N95 masks are still best saved for the healthcare staff as there are so many workable options available to the public. See the October article in Nature for some comparisons of materials.
A brief note about masks and children
The literature is generally in agreement that very young children (2 -3 years of age and younger) should not be masked due to the risk of suffocation. The American Academy of Pediatrics and the Italian Pediatric Society have published statements about masking in children and recommend masking for children older than 2 (the American Academy of Pediatrics) or 3 (The Italian Pediatric Society). It would be a good idea to check with your pediatrician if you have concerns about your children.
Common mask objections:
Can masks cause decreased blood levels of oxygen, increased carbon dioxide levels? There is no evidence of this and indeed studies have been performed using pulse oximeters to measure levels during daily activities and exercise. Pulse oximeters, devices that measure blood oxygen levels, can be found very inexpensively online and you can wear one while masked to check this out for yourself.
Viral particles are way too small to be blocked by mask – so using a mask to block them is like trying to block mosquitoes with a chicken wire fence. I have seen this exact argument on social media. As we mentioned before viral particles do not travel by themselves. Viruses need a host and those particles are expelled in droplets or aerosols.
My friend contracted the virus even though they wore a mask. As mentioned above masks do not provide 100% protection and they are more effective at protecting from release of particles rather than blocking inhalation of particles in the environment. Partial protection is better than no protection.
Masking decreases the immune system activity – it’s like living in a bubble so my immune system will be weakened. The immune system is indeed stimulated by contact with environmental materials. A partial block of environmental materials, such as a mask provides, does not dampen immune system activity. You are still being exposed to materials by touch, through food and beverage and even in your own home.