Year : 2020 | Volume
: 9 | Issue : 4 | Page : 311--315
Face masks in corona virus disease-19 infection
M Suresh Babu
Department of Medicine, JSS Medical College & Hospital, JSSAHER, Mysuru, Karnataka, India
M Suresh Babu
Professor of Medicine, JSS Medical College & Hospital, JSSAHER, Mysuru - 570 023, Karnataka
The fear and panic created by COVID-19 has made people to use all kinds of masks available in the market without knowing their utility in offering protection against COVID-19. This review is intended to inform the readers about the different types of masks available, types of mask to be worn by different sections in the society and the latest information available on the role of masks in preventing the spread of COVID-19.
|How to cite this article:|
Babu M S. Face masks in corona virus disease-19 infection.Int J Health Allied Sci 2020;9:311-315
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Babu M S. Face masks in corona virus disease-19 infection. Int J Health Allied Sci [serial online] 2020 [cited 2020 Nov 25 ];9:311-315
Available from: https://www.ijhas.in/text.asp?2020/9/4/311/298123
The corona virus disease-19 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus-2 (SARSCov-2). The causative virus COVID-19 is transmitted through droplets when an infected person coughs, sneezes, or exhales. These droplets are too heavy to get suspended in the air and fall on floors or surfaces after their release. A person can get infected either by breathing in the virus or by touching a contaminated surface and then your eyes, nose, or mouth. Available information from the present pandemic indicates that this virus is spreading more efficiently than influenza. The best way to prevent the illness is to adopt preventive measures such as social distancing, regular washing of hands, and wearing a mask. Handwashing alone is shown to decrease the risk of SARS virus transmission by 55%, wearing a mask by 68%, and with handwashing, wearing a mask, gloves, and a protective gear by 91%. Wearing a mask is therefore a very important way of preventing the spread of COVID-19. A risk assessment model for an influenza epidemic had demonstrated that if people do not wear a mask, around 35% of the people will contract the influenza infection, while the prevalence of infection will decrease by 50% if 50% of people wear mask and the risk of transmission becomes negligible if 80% of the people in the community wear a mask.
The health scare created by COVID-19 has made people to use all kinds of masks without being aware of how much beneficial they are in prevention. This review article helps the readers understand the different types of masks available and the recommendations about the usage of different types of masks by different sections in the society to optimize the resources available in preventing the spread of COVID-19.
The Dust Mask
A dust mask is a flexible paper pad held over the nose and mouth by elastic or rubber straps used in avoiding nontoxic nuisance dusts present during house dusting, grass mowing, gardening, sweeping, brickwork, fiberglass, construction activities, and during sand storms. This mask does not offer any protection against COVID-19 and should not be used, though many people are using it with a belief of protection with its usage.
The Single-Layer Face Mask
The single-layer face mask is made up of a single layer of nonwoven fabric or wood pulp tissue paper and is usually used in the food processing industry. It is to be used only for single use and should never be washed and reused. It offers no protection against corona virus though many people are using it with a belief of protection with its usage.
There is a need for the large sections in the society for a cheap, easily available, washable, and reusable mask. Cloth masks fulfill these requirements. The Office of the Principal Scientific Advisor to the Government of India has recently released a manual for homemade cloth masks. The manual gives advice on how to make homemade cloth masks using an old T-shirt or cotton vest (the fabric must be 100% cotton) and how to clean and sanitize the mask on a daily basis. One can include as many layers of the cloth, but the more the number of layers, the more difficult it becomes to breathe through it. Depending on the thickness of the fabric, two or three layers are desirable. Cotton masks are available in many stores across the country.
Surgical Mask or Medical Mask
A surgical mask, also known as a procedure mask, medical mask, or simply as a face mask, is a loose-fitting, disposable mask that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the surrounding environment. A surgical mask will help in avoiding large-particle droplets, splashes, and sprays containing germs (viruses and bacteria) reaching the mouth and nose and also help in reducing exposure of your saliva and respiratory secretions to others. They are not designed to protect the wearer from inhaling airborne bacteria or virus particles and are less effective than respirators, such as N95 or filtering facepiece (FFP) masks, which provide better protection due to their material, shape, and tight seal. Modern surgical masks were started to be used in the 1960s. Contrary to popular belief, the surgical mask was never intended to protect the surgeon from catching the patients' infection but was meant to protect the patient in case the surgeon coughed or sneezed during the surgery. However, the surgical mask protects the surgeon from blood and body fluid splashes entering into their nose and mouth from the surgical site during surgery. Surgical masks are made in different thicknesses which has an effect on how easily one can breathe through the face mask and how well the protection it provides. The surgical mask is made of three layers. The innermost layer is made up of an absorbent material that absorbs moisture from the wearers breath, the middle layer is made up of a melt-blown material that acts as a filter, and the outer layer is made up of material that repels liquid. The pleats are intended to increase the surface area to cover the nose and chin adequately. It is held in place by strings either looping around the ears or tied behind. There are varying levels of quality for surgical masks and the extent of protection depends on the specification of manufacture. Surgical masks need to conform to the following quality standards: bacterial filtration efficiency >98%, particulate filtration efficiency <99% for 0.1 micron particle size, differential pressure that measures ease of breathing <3 mm, and fluid resistance of 80 mmHg. In the USA, the Food and Drug Administration sets standards and certifies the surgical masks, while at present, there is no certifying body in India for surgical masks. The surgical mask does not offer a tight fit with space for the air to leak from all sides of the mask and not designed for self-protection. Surgical masks are intended to be used only once and then safely disposed. They should not be washed and reused. The life of a surgical mask varies according to its use, but usually lasts between 3 and 8 h depending on the environmental humidity, temperature, and volume of air breathed. The proper way of using this mask is to clean the hands with soap and water or an alcohol-based hand rub before putting on the mask and ensure that there is no or minimal gap between the face and the mask. Touching the mask from outside should be avoided, and if one does, hands should be cleaned with soap and water or alcohol disinfectant. If the mask becomes damp or gets soiled, it has to be disposed of in a closed bin. The mask has to be removed from behind without touching the mask followed by washing of hands with soap and water or alcohol rub.
How to Know If a Surgical Mask Is Real or Fake?
First, the face mask has to be torn down to check if it has 3-ply layers. Second, the layers of the mask have to be checked to see if there is a melt-blown filter layer. It can be tested further by pouring some water on a mask and holding it. If genuine, there will be no leak. With the mask on, blowing some air while turning on a lighter on the other side, puts out the lighter, then the mask is not genuine. More information on ways to recognize fake surgical masks can be accessed in this YouTube video.
Respirator Mask (N95, N99, N100; Filtering Facepiece 1, Filtering Facepiece 2, Filtering Facepiece 3)
A respirator mask is a tight-fitting mask with a filtration system that prevents the user from being exposed to noxious particles, gases, oils, or microorganisms, including bacteria, viruses, and fungi. It has a tight fit, so that air does not leak from the sides into the nose and mouth. The filter of the N95 mask is made up of millions of microfibers of polypropylene layered on the top of each other that are permanently electrostatically charged. The electrical charge helps in retaining its ability to filter microorganisms or microparticles. Respiratory masks are certified into N, R, or P depending on their ability to offer resistance to oil-based particles. N stands for not oil resistant which can only be used for particles that do not contain oil. R stands for somewhat resistant to oil and P stands for strongly oil proof. P and R are used only for industrial settings. N is further divided into N95, N99, and N100 depending on their filtration efficacy. N95 means that this mask can filter off at least 95% of particles which are >0.3 microns, while N99 means that it can filter off 99% of these particles. The 0.3 μm cutoff is used for measuring filtration efficacy because that is the most penetrating size into the lungs. The coronavirus is between 0.06 and 0.14 microns in diameter or 60–140 nm. Viruses of this size are easier to be filtered than those that are >0.3 microns as these sized particles follow a Brownian motion (random zig-zag) and therefore get trapped more easily in filters. N95, N99, N100, FPP2, and FFP3 masks filter the corona virus effectively. Each country has their own certification standard for each mask type, e.g., USA (NIOSH42CFR Part 84), Europe (149:2001), China (GB2626). As of now, India does not have any certification standard or certifying body for respiratory masks. The European Union classifies respirator masks into FFP1, FFP2, and FFP3 where FFP stands for FFP. N95 is roughly equivalent to FFP2 and N99 is roughly equivalent to FFP3 masks. FFP1, FFP2, and FFP3 are also called P1, P2, and P3, respectively. Although N95 and similar masks are efficient in protecting the user against viruses, they are not easy to breathe and often get moist and hot after wearing it for more than 30 min. They are therefore not meant for everyone and are mainly for health-care providers who come in close contact with the COVID-19 patients.
General N95 Respirator Precautions
People with chronic respiratory, cardiac, or other medical conditions who have breathing difficulties should check with their health-care provider before using an N95 respirator as the N95 respirator can make it more difficult for the user to breathe. Some models have exhalation valves that can make breathing out easier and help reduce heat buildup. N95 respirators with exhalation valves should not be used when sterile conditions are needed as during exhalation they allow the virus to pass out easily and potentially infect people around. N95 respirators are not designed for children or people with facial hair as a proper fit cannot be achieved in them and may not provide full protection.
Fake N95 masks: In view of the increasing demand for N95 masks, some dubious companies are making fake N95 masks. A respirator that has N95 written besides it is not enough to certify its validity. It is often made with cheap fabric and duplicate parts to dupe the consumer. The situation is similar across the world and fraud alerts have been issued by several governments. The N95 mask should be NIOSH approved and CE certified. NIOSH has a website which has a list of certified license holders to manufacture the N95 mask. The important thing to identify is the TC number on the particular mask. Using this TC number marking on the respirator, one can go to the CDC website and search its validity. A genuine N95 respirator mask should have all the markings mentioned below.
Extended Use and Limited Reuse of N95 Masks
Extended use refers to the practice of using the same N95 respirator for repeated examination of several patients, without removing the respirator in between. Extended use may be implemented when multiple patients are infected with the same respiratory pathogen and patients are placed together in dedicated waiting rooms or hospital wards. Reuse refers to the practice of using the same N95 respirator for multiple encounters with patients but removing it (”doffing”) after each encounter. The respirator is stored in between encounters to be put on again (”donned”) prior to the next encounter with a patient. Ideally, the N95 respiratory masks are only for single use, and this should be the standard practice whenever possible. With the present COVID-19 pandemic, as N95 and FFP2 masks were in severe short supply, many research groups have experimented with different ways of extending its use without compromising on the protection that it offers. Necessary requirements for its extended use and reuse include maintaining its fit and filtration function, the sterilizing method must eliminate the virus threat, be harmless to the end user and retain respiratory integrity. It should only be used by the same wearer and not be shared with others. If the N95 mask is soiled or damaged or makes breathing difficult (because of filter clogging), it should be discarded and no attempts should be made to sterilize it for reuse. The different ways of sterilizing and reusing the N95 mask are as follows.
This is a simple way of reusing the N95 respirator mask. Because coronaviruses lose their viability significantly after 72 h, many organizations have promoted a rotation and reuse strategy. CDC suggests that masks can be reused up to five times. Drying the mask kills the virus, but it takes at least 48 h to dry. Therefore, drying in a clean, dry place for 72 h (3 days) and then reusing it is one way of reusing the mask. With four N95 masks, one can be used every day and then kept for drying, until the fourth when it can be reused. The mask has to be kept in a paper bag away from direct sunlight and ultraviolet rays. If the mask becomes soiled, damaged, or becomes difficult to breathe, it has to be discarded. Hand hygiene before removing and wearing it again has to be practiced. Other ways of sterilizing it are as follows.
Heating in an oven
Heating at 70°C for 30 min kills the virus.
Dry heat in a rice cooker
Put the N95 mask in a traditional electric rice cooker without putting any water inside for 3 min, until the temperature is 149–164°C.
Chemical Sterilization With H2O2
Are surgical masks as good as N95 masks for health-care providers?
There are no published head-to-head trials in SARS-CoV-2 infection. A recent systematic review and meta-analysis of surgical masks versus N95 respirator masks by the Chinese Cochrane Centre showed that there was no difference in the efficacy between surgical masks and N95 masks in preventing laboratory-confirmed respiratory viral infections when worn regularly, adhering to proper standards of wearing and removing them.,
Who should wear masks and which one?
World Health Organization updates guidance on masks for health workers and the public
The World Health Organization (WHO) has recently (June 05, 2020) shared new guidance regarding mask wearing for health workers and the general public based on a review of evolving evidence.
Those who are sick should wear a mask if they must go out. (Ideally, however, those who are sick should stay at home and those confirmed to have COVID-19 should be isolated and cared for in a health facility and their contacts quarantined)Home caregivers should wear a mask to protect themselves and prevent further transmissionIn areas with widespread transmission, the WHO advises medical masks for all people working in clinical areas of a health facility and not only workers dealing with patients with COVID-19In areas with community transmission, the WHO now advises that members of the general public aged 60 years and older and those with underlying conditions should wear a medical mask in situ ations where physical distancing is not possibleThe general public should wear nonmedical masks where there is widespread transmission and when physical distancing is difficult, such as on public transport, in shops or in other confined or crowded environmentsAdditionally, the WHO has released new guidance on cloth masks, recommending that they consist of at least three layers of different materials: an inner layer being an absorbent material like cotton, a middle layer of nonwoven materials such as polypropylene (for the filter) and an outer layer, which is a nonabsorbent material such as a polyester or a polyester blend.
To conclude, N95 mask reduces the transmission of aerosol by 70%, whereas surgical mask reduces transmission by 50% and cotton masks by 40%. Maximum protection from catching the infection from others by the aerosol route is offered by the N95 mask (99%), whereas the surgical mask offers 75%–80% protection and the cloth mask by around 50%–70%. Masks must be worn correctly, cared for and kept clean to ensure they are effective. Wearing a mask with social distancing and regular washing of hands form the cornerstone in successful containment of spread of COVID infection.
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