Masked people are suddenly to be seen everywhere. Across the world, people have taken to wearing face masks of one sort or another. These masks come in various sizes, shapes and colours, some even aesthetically rather pleasing. This new-found demand means that masks are in short supply. Panic buying has led shops to run out of stocks. Online purchases have skyrocketed, while prices have risen steeply. Many creative methods of DIY masks manufacture, using household materials, are being recommended. Bras and sanitary towels, among other readily available products, have even been repurposed as masks. It seems the right time to take a detached look at face masks and try to understand the rationale for their use in the light of the Coronavirus pandemic.
The commonest type of mask in use, and that with the longest pedigree, is the surgical face mask- a disposable, loose-fitting, mask that is designed to cover the nose and mouth. The mask creates a physical barrier, protecting others from the wearer’s saliva and respiratory secretions (sputum, nasal discharge). The surgical mask of today dates back to the 1890s, when it was first recognised that bacteria-laden droplets, issuing from the nose and mouth, could transmit infection. The first masks in surgical use were made from one or more layers of cloth or gauze and were worn to prevent post-operative infection. Over time, face masks came to be routinely worn by operating room staff during the course of surgical procedures. Cloth and gauze masks are, however, no longer recommended for use by healthcare workers, except as a last resort.
Today’s surgical masks are made with two to four layers of non-woven and filtering synthetic plastic mesh. These masks can be held in place either over the ears by loops of string or secured to the head by fabric straps or elastic headbands. Non-surgical members of the public may choose to wear these masks to protect themselves against the inhalation of airborne particles (atmospheric pollution) or aerosolised droplets (airborne diseases). Cultural factors may influence the liberal public use of face masks. In several East Asian countries, such as China, Taiwan, Japan and South Korea, masks are worn throughout the year, whatever the occasion, and have even become fashion accessories. Masks are, however, not as protective as many of their wearers believe them to be. In fact, surgical masks can allow air to leak along the sides as it follows lines of least resistance. Masks also frequently become moist or are otherwise soiled and damaged when worn for any length of time. In addition, touching the front of the mask contaminates the hands of the wearer and facilitates further disease transmission.
Wearers can only be reliably protected by respirators, or respirator masks, which can be either disposed of after a single use or reused for a limited period of time. These devices are recommended for healthcare workers, those likely to come in contact with people actually or potentially infected with Covid-19 . Supply of respirators has failed to keep up with increasing demand, leading to a well-publicised delay in providing personal protective equipment to frontline NHS staff. Respirators effectively filter airborne particles, while forming an air- tight seal around the wearer’s mouth and nose, but have to be fitted properly and put on (donned) and taken off (doffed) correctly to be of any benefit. This means that all users have to be trained in their use and must wear face-fit-tested respirator masks to benefit from their use.
The respirator masks most often used are the N95 and the FFP3, either of which filters out 95 per cent of all inhaled particles of 0.3 micron or larger in diameter. These masks protect against respirable dust, smoke and aerosol particles, but not against vapour and gas. The majority of so-called pathogens, including bacteria, viruses and fungal spores, are filtered from the inhaled air, thereby effectively protecting the wearer. Respirators have to meet standards of production, and come with safety ratings, thereby ensuring that they are “fit for purpose”.
There seems to be some confusion about the wearing of masks. The WHO and CDC recommend that only those with Covid-19 symptoms or those caring for them should wear masks. On the other hand, in parts of China and in the Czech Republic, for example, the wearing of masks in public spaces by seemingly healthy people is now mandatory, despite many suggestions that surgical masks do not actually protect their wearers. Mask wearing has a lot to do with human psychology. When masks are being worn by everyone else, it is difficult to find fault with people trying to follow suit. The desire to “protect” oneself at any cost is the most basis of all human desires, even though in this case it often only provides a false sense of security. Meanwhile, hand washing, cough etiquette and social distancing still remain the most important protective measures against the coronavirus.
Ashis Banerjee
PS: In a new twist, on 4 April 2020, the CDC recommended the use of cloth face coverings as a means of protection in public settings where social distancing measures may be difficult to enforce, such as in grocery stores and pharmacies. These coverings can be fashioned from readily available household materials, such as scarves-as suggested by President Trump-and do not have to be surgical masks. While the decision to wear a facial covering is an individual choice, made voluntarily, in many other parts of the world the use of surgical face masks is increasingly being enforced by the state, irrespective of choice. It remains important to keep up with the latest local and official recommendations.