Know Your Masks: Protection in the Time of Omicron
One may wonder if one even needs to wear a mask in the day and age of vaccines. However, many experts agree it is important that one keeps wearing a mask, even if vaccinated.
Making masks a mandate in certain states has been backed by former Food and Drug Administration (FDA) Commissioner Scott Gottlieb, M.D., in the midst of the recent COVID-19 surges across the U.S. In a recent report, Acting FDA Commissioner Janet Woodcock, M.D. addressed the issue, saying, “With the current wave of the omicron variant, it’s critical that we continue to take effective, life-saving preventative measures such as primary vaccination and boosters, mask-wearing and social distancing in order to effectively fight COVID-19.”
Yes, vaccines are the first and foremost line of defense against COVID-19. However, they do not guarantee complete protection against infections. The currently authorized vaccines were formulated on the basis of the Wuhan strain of the virus, which has now undergone multiple mutations. The current scenario has seen a surge in cases of the Omicron variant, which consists of more than 30 mutations in its spike protein alone and has been found to be 4.2 times more transmissible in the early stages.
If one is vaccinated and still catches COVID-19, it is possible they can transmit the virus to others if they sneeze, cough or come in close contact. However, if one is wearing a mask, this risk can be lessened.
The Centers for Disease Control and Prevention recommends wearing a mask in health care settings and other places where people around may have risk factors for severe consequences of COVID-19. These include people over the age of 65 and those living with cardiovascular complications, diabetes, obesity, chronic lung disease, weakened immune systems or cancer.
All about masks:
Masks come in many different types. Respirators, single-use, respiratory protective devices designed to fit closely to the nose and face (with the edges sealed around the nose and mouth), are highly efficient in preventing particle sizes up to 0.3 micron from entering the respiratory system, with designations N-95, N-99, N-100. N is one of the respirator rating letter classes, standing for non-oil (indicating the use of these masks in the presence of non-oil particulates). Other classes include R (denoting resistance to oil) and P (oil proof). The number following the respirator class letter denotes the efficiency of the respirator in filtering particulates challenged with 0.3 micron particles as per ASTM standard F2299 For example, N95 denotes that the mask can effectively filter out 95% of the non-oil particulate.
Some N95 respirators have exhalation valves for ease of breathing. These should be used by people with cardiovascular complications or pre-existing breathing issues. However, it should be kept in mind that people working in areas where sterilization is needed should not wear such masks. Most masks cleared by the FDA are single-use masks. A subset of respirators known as surgical respirators are exclusively meant for people working in healthcare settings. People with extensive facial hair and children should not use such masks as the fit will not be adequate.
Surgical masks are disposable and made to provide a physical barrier between the nose and mouth of the healthcare worker, especially surgeons and staff in emergency rooms and hospitals, and their surroundings, in order to prevent potential contamination and entry of pathogens. These masks are made with of three layers of varying thicknesses. The three layers include a melt-blown polymer, mostly polypropylene placed in-between two layers of nonwoven spun bond
polypropylene fabric. This can prevent the wearer from coming in contact with larger liquid droplets, aerosol and sprays through inhalation, surgical procedures or through the mouth. Hence, any form of bacteria or virus gets entrapped within and is prevented from entering the wearer’s system. These masks should not be shared with anyone else and disposed of after use. A disadvantage of these masks is that they cannot trap some of the smaller droplets spread through sneezes, coughs and some medical/surgical procedures. Surgical masks have been tested as per NIOSH standards for filtration efficiency but have not made the cut for respiratory infections. They are not designed to protect the wearer from inhaling airborne bacteria or viruses and are less effective than respirators.
A study of surgical masks conducted by researchers at the University of Minnesota demonstrated the generation of particles from healthy subjects, ranging from 0.09 to 3 μm. Concentrations ranged from 100 to 350 particles/L during normal breathing and 150 to 2000 particles/L while talking or coughing, and sometimes ranging from 14 to greater than 3000 particles/L and an average particle size of 0.32 μm. The filters of most of these surgical masks allowed a large majority of wearer-generated particles to penetrate and collected only a small percentage of airborne particles generated by infectious patients. Even when equipped with filters demonstrating relatively high collection efficiency, 10 to 40% of particles penetrated the face seal as a result of poor fit.
As of October 25, 2021, the CDC recommended the average person wear a mask that has two or more layers of washable, breathable fabric. While this would seem to include cloth masks, experts are questioning their effectiveness against the highly infectious omicron variant. “Cloth masks are little more than facial decorations. There's no place for them in light of Omicron,” said Dr. Leana Wen, a CNN medical analyst. Wen recommends wearing at least a three-ply surgical mask.
“Researchers are still pinpointing exactly how much more infectious omicron is than its predecessors, but at this point, it’s clear that omicron is indeed more infectious — which means we all need to be taking additional precautions,” said Dr. Steven Gordon, M.D., an infectious disease physician at the Cleveland Clinic. However, he added that the CDC still recommends N95 masks be prioritized for healthcare workers.
A few key points to keep in mind before masking up:
- The nose and mouth should be covered/sealed adequately to prevent entry of pathogens in closed or crowded spaces. The nose-clip/face seal is a crucial determinant for mask efficiency
- Respirators should be prioritized for healthcare professionals and high-risk patients
- People with lower risks should wear cloth masks coupled with surgical masks if necessary; if attending closed groups, gatherings or ceremonies, wear a respirator over a surgical mask
- Being fully vaccinated does not guarantee complete protection against COVID-19