Here in the US we have reached staggering numbers of people infected and killed by COVID-19. As of the date of writing this article since January 21, 2020 we have had over 8 million cases and close to 220 thousand deaths. (cover.cdc.gov).
There is no question in any rational human being’s mind that this is a deadly airborne virus that is transmitted and contracted primarily by being exposed to other sick people who are breathing droplets into the air (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293495/).
Because it is very contagious and has a relatively long incubation period, COVID-19 is easily spread by people who are asymptomatic or pre-symptomatic. There is widespread agreement among the majority of medical professionals that the best way to avoid exposure to the virus is to take common sense steps to protect yourself and others.
These include wearing masks, social distancing and washing hands. The data on whether or not masks reduce infections is pretty indisputable, at this point. Unfortunately, due to the anti-science misinformation of many on both sides of the political spectrum, mask wearing has become a symbol of pushback against authority.
And this has eroded the basic truth that masks are effective. This isn’t a matter of “opinion”, it’s factual. And wearing masks should never have been made into a political signal, it is above all a simple technique for reducing risk.
People don’t dispute that having a safety on a trigger of a gun prevents more accidental gunshots or that seat belts save lives during car accidents. It’s common sense. The same should be true for masks, they work and are a simple and effective way of reducing exposure.
Both the CDC and the WHO both recommend wearing cloth masks. While both of these organizations have been under attack by the forces of misinformation, their recommendations are based on what the science has told us about the efficacy of masks (https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fcoronavirus%2F2019-ncov%2Fprevent-getting-sick%2Fcloth-face-cover.html)
Early on in the pandemic, mask wearing was not encouraged by the CDC because there were shortages of masks for professionals and there was some confusion about how this new virus is spread. That is no longer true. They learned from their experience and like any good scientist, they re-evaluated their position.
Here’s Several Reasons Why Masks Work
There are several different reasons why masks work (https://files.fast.ai/papers/masks_lit_review.pdf). Firstly, there is ample data from laboratory studies of respiratory droplets and the ability of masks to block them. One experiment using high speed video found that hundreds of droplets ranging from 20 to 500 micrometers were generated just by simply speaking a simple phrase, but almost all of these drops were blocked when the mouth was covered with a washcloth. (https://www.nejm.org/doi/full/10.1056/NEJMc2007800)
Another study of people who had the flu or common cold found that wearing a surgical mask significantly reduced the amount of respiratory viruses in droplets and aerosols. (https://www.nature.com/articles/s41591-020-0843-2#Sec3)
Those studies are based on what was found, largely, in a laboratory. But, actually, the strongest evidence for mask wearing is found by looking at what they have done in real life scenarios, i.e., the actual epidemiological data. These are basically experiments in nature.
A recent study published in The Health Affairs Journal compared COVID-19 growth rates in 15 states before and after they implemented mask mandates. This showed an immediate reduction in Coronavirus growth rates at .9 per cent after 5 days and by 2 per cent after three weeks. (https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818)
Another study looked at coronavirus deaths across 198 countries and the data was clear. Countries with widespread acceptance of mask wearing had lower death rates. Period. (https://www.researchgate.net/publication/342198360_Association_of_country-wide_coronavirus_mortality_with_demographics_testing_lockdowns_and_public_wearing_of_masks_Update_June_15_2020)
Masks Protect Everyone Involved
One thing that is also clear about masks is that they help protect others. They are effective at what is known as “source control”. In other words, they can prevent larger droplets from evaporating and spreading.
Finally, two case studies show this dynamic in action. In the first, a man flew from China to Toronto and when he arrived he tested positive for COVD-19. He had some symptoms (a dry cough) and wore a mask. 25 people who tested sat near him on the flight all tested negative.(https://www.cmaj.ca/content/192/15/E410)
In another case study, two hairstylists in Missouri tested positive for Covid-19 and exposed 140 clients. Both the stylists and the clients wore masks. No one else tested positive. (https://www.washingtonpost.com/business/2020/06/17/masks-salons-missouri/)
We also see this in the real world with protests. Most of the protests over the summer did not cause large spread of the virus because many people wore masks. In contrast, the Rose Garden event at the White House which is now considered a “super spreader” event had virtually no one wearing masks or social distancing and over 2 dozen cases have been traced to that event.
Bottom Line: Laboratory experiments, real world experience and epidemiologists all agree that masks work. However, some masks are better than others. In my next post we’ll compare and contrast different types of masks and different materials and take a look at which are the most effective.
