by Dr. Paul Han
Face masks might be the among the most important defensive tools for protecting our community. Currently, both the World Health Organization (WHO) and the Center for Disease Control (CDC) recommend the use of face masks by the public to help prevent the spread of COVID-19. Countries (like Korea) that adopted mask use earlier have been much more successful at controlling the spread of disease. In the last few months, mask use has become more widespread in New York and New Jersey. However, a variety of different types of masks are available, and the different choices can cause confusion.
Face masks can generally be divided into three different categories: small-particle masks, surgical masks, and cloth masks. Small particle masks (which include N95, KN95, and KF94 masks, depending on the national standard applied) are designed to filter out 0.3-micron particles. Such particles are considered to be the most dangerous, because the size of those particles tend to penetrate deepest into the lungs. However, N95 masks (and the equivalents) are more difficult costly, difficult to obtain, and more difficult to use. These masks always require a tight seal around the mask to be effective. Surgical masks are designed to protect against bodily fluids and water droplets. These masks are generally much more comfortable and widely available. Cloth masks are not standardized and vary in efficacy.
For most people, the surgical mask is considered to be the best choice for protection against contagion. Because viruses are transmitted via water droplets, the use of surgical masks is effective for protection from COVID-19 and can decrease viral shedding from patients who are sick. Small particle masks reserved for high risk exposures for short intervals. In fact, in health care workers exposed to different viruses, surgical masks have been found to be just as effective as small particle masks. Cloth masks may be effective, but since they do not undergo rigorous testing, the effectiveness is unknown. However, masks with expiratory valves in any category (whether small particle, surgical, or cloth) should be avoided, because the valves open to release droplets during expiration.
When using the masks, the wearer should be careful not to touch the outside of the mask, which can be contaminated. When adjusting the mask, only touch the edges. Surgical or N95 masks should be discarded if wet, soiled, or compromised in any other way. But as long as the masks remain intact, there is no time limit on any mask. Both N95 and surgical masks have been shown to be useful for long periods of time. Cloth masks can be reused but care must be taken when washing these masks. Re-using surgical or N95 masks is not recommended because of the risk of contamination.
Perhaps the most important factor in choosing a mask is finding one that is comfortable. Many people will touch, adjust or partially remove masks that are uncomfortable. Because the masks can interfere with speaking, some people remove the masks when they are on the phone, which makes the masks ineffective. These days, many manufacturers are developing masks from different materials. Aside from the covering itself, some masks have adjustable straps. In addition, the straps can be placed on extenders or holders to prevent irritation behind the ears. In this respect, the best mask is the one that you will wear.
The saddest part of wearing these masks is that nobody can see each other’s face. Because so much emotion is conveyed by the mouth, communication has become much more difficult. Many masks have graphics, to show a little more personality. But to help with communication, the best advice I have heard is to learn to smile with your eyes.
Because COVID-19 virus is often asymptomatic, many people will not know they are spreading this virus. This is one of the reasons that COVID-19 spread so quickly and widely. Using masks could help stop the spread of this disease. And choosing the right mask may actually save your life.
Zhang R et al. Identifying airborne transmission as the dominant route for the spread of COVID-19. PNAS June 30, 2020 117 (26) 14857-14863; first published June 11, 2020 https://doi.org/10.1073/pnas.2009637117
Leffler, Christopher et al. Country-wide coronavirus mortality and use of masks by the public. Preprint. 10.13140/RG.2.2.35208.37125.
Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med 26, 676–680 (2020). https://doi.org/10.1038/s41591-020-0843-2
MacIntyre CR et al. A Cluster Randomised Trial of Cloth Masks Compared With Medical Masks in Healthcare Workers BMJ Open. 2015 Apr 22;5(4):e006577. doi: 10.1136/bmjopen-2014-006577.
Bartoszko JJ, Farooqi MAM, Alhazzani W, Loeb M. Medical masks vs N95 respirators for preventing COVID-19 in healthcare workers: A systematic review and meta-analysis of randomized trials. Influenza Other Respir Viruses. 2020;14(4):365-373. doi:10.1111/irv.12745
Wegrzyn et al. Mapping the emotional face. How individual face parts contribute to successful emotion recognition. PlosOne 2017; May 11. https://doi.org/10.1371/journal.pone.0177239
Paul Han, MD, FCCP
Pulmonary Specialists of North Jersey
Sethuraman, Nandini; Jeremiah, Sundararaj Stanleyraj.
Interpreting Diagnostic Tests for SARS-CoV-2. JAMA:
May 6, 2020.