Mask Up, Mask Up

02-21-2021Nurse's LetterShannon David, RN, NCSN

Over the past several weeks, the 7th & 8th graders have been busy conducting trials, gathering data and observing the outcomes of experiments to prepare for the upcoming Science and Engineering Fair. Having a basic understanding of the “Scientific Method”--how hypotheses are formed and tested--is important for all, not just those who seek a future occupation in the scientific disciplines. This is no more apparent than during the current Pandemic. From the onset, we have been inundated with reports and updates, research, studies, trials and experiments, often confusing, at times contradictory. Knowing how to return to, read and interpret, the source of a report is an invaluable skill.

About 10 days ago, multiple news outlets led with headlines indicating that the CDC was recommending “double-masking”--the wearing of a disposable medical mask with a cloth mask over it--as increased protection against the spread of coronavirus. “Two masks is the new mask” is the slogan and the practice was quickly made a requirement in some places. Several parents called at the beginning of this week to see if they needed to have their child wear two masks to school. Wait, wait. What, what?

On February 10, 2021, as an early on-line release, the Centers for Disease Control, in it’s Morbidity and Mortality Weekly Review (MMWR) published results of a scientific experiment designed to support the hypothesis that “Wearing a mask that fits tightly to your face can limit the spread of the virus that causes COVID-19” MMWR 02/19/21. The experiments, according to researchers, were designed to “assess two methods to improve medical procedure mask performance by improving fit and, in turn, filtration”. The two methods they chose were: 1) double masking and 2) knotting the medical procedure mask close to the corner of the mouth and tucking in the sides of the masks. All experiments were done using a “pliable elastomeric headform”--a dummy or mannequin--that is fitted with a plastic mouthpiece that emits an aerosol during a simulated cough.

Results indicate that “In lab tests with dummies, exposure to potentially infectious aerosols decreased by about 95% when they both wore tightly fitted masks” either a cloth mask over medical procedure mask OR a single medical procedure mask with knotted ear loops and tucked in sides. The findings in these laboratory based experiments certainly provide evidence that mask “fit” is of great importance. Note that BOTH the double-mask and the single medical mask, knotted, performed equally well. Why, why, then would “double-masking” be chosen over a single mask adapted to fit snuggly? Further, as every scientist knows, recognizing the limitations of an experiment and the variables that impact outcomes, are important aspects of the Scientific Method. The researchers in these experiments acknowledge that results are subject to at least four limitations: 1) only one type of medical procedure mask and cloth mask were used 2) no other mask combinations were considered (i.e. cloth over cloth, medical procedure mask over medical procedure mask) 3) the findings might not be generalizable to children or men with facial hair and 4) “double masking might impede breathing or obstruct peripheral vision for some wearers”. Did #4 cause you to do a “double-take”? Therein lies the problem. There is nothing wrong with the experiment as it was designed and conducted, but it needs to be looked at as theoretical in nature. There are things we can do to crash test dummies, CPR mannequins and pliable elastomeric headforms that we wouldn’t necessarily do to the living and breathing. The takeaway is this: Wear a well-fitted mask over your nose and mouth when you are in close proximity to another person. If you need a reminder on mask basics, please re-watch the video on our YouTube channel. Having entered the Holy Season of Lent, if we are to double up on anything--let’s make it our prayers!

Our Lady of Mt. Carmel, pray for us!