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Covid-19: Use of face mask  

| Updated: April 13, 2020 21:26:39

Covid-19: Use of face mask   

Coronavirus disease (COVID-19) is an infectious disease caused by the most recently discovered coronavirus. It was unknown before the outbreak began in Wuhan, China, in December 2019.  The World Health Organisation (WHO) has already declared it a pandemic. Since December until April 05, 2020, more than 1.09 million confirmed cases of infection, including 58,620 confirmed deaths have been reported in 209 countries, areas or territories.

Primarily, it spreads from person to person through small droplets of saliva or discharge from the nose, when an infected person coughs, sneezes or exhales. These droplets land on objects and surfaces around the person. Other people get infected by touching these objects or surfaces and then touching their eyes, nose or mouth. People can also get infected by the virus if they breathe in droplets.

Till date, there are no specific vaccines or treatments for Covid-19. So, the utmost need is to prevent and slow down the transmission by protecting ourselves from infection by frequent hand washing using soap and water or an alcohol-based sanitiser, not touching face, wearing mask, practising respiratory hygiene, maintaining social distance etc. Masks and other protective equipment can help stop the spread of coronavirus.

Two types of masks are generally available to prevent respiratory infection: surgical and respirators. Surgical mask, also known as a procedure mask, medical mask or simply as a face mask. Most surgical masks adopt a three-layer design which includes an outer fluid-repelling layer, a middle layer serves as a barrier to germs, and an inner moisture-absorbing layer. Face mask is a loose-fitting, disposable device that covers the mouth and nose of the wearer and creates a physical barrier with the immediate environment. If properly worn, it may be effective in preventing transmission of respiratory viruses and bacteria, more commonly that spread via droplets, which travel short distances and are transmitted by cough or sneeze. It also prevents the wearer from spreading large sprays and droplets, as well as hand-to-face contact.

Respirators-N95 respirator blocks 95 per cent of airborne particles. They are tight fitting and prevent inhalation of smaller infectious particles that can spread through the air over long distances after an infected person coughs or sneezes. Diseases that require use of an N95 respirator include tuberculosis, chickenpox and measles.

Since the Covid-19 outbreak, the use of face mask has become ubiquitous. Recommendations on face masks vary across countries and it is observed that the use of masks increases substantially once local epidemics begin, including the use of N95 respirators (without any other protective equipment) in community settings. Despite the consistency in the recommendation that symptomatic individuals and those in health-care settings should use face masks, discrepancies were observed in the general public and community settings in different countries across the globe.

World Health Organisation (WHO) recommends  only two types of people should wear masks, those who are sick and show Covid-19 symptoms or those caring for people suspected to have the coronavirus. The Centers for Disease Control and Prevention (CDC) of the USA do not recommend that people who are well wear a face mask to protect themselves from respiratory diseases, including coronavirus (Covid-19). Furthermore, CDC does not recommend that the general public wear N95 respirators to protect themselves from respiratory diseases, including coronavirus (Covid-19).

Reasons for discouraging universal or community-level use of face mask include: preservation of limited supplies for health care settings and prevent  a false sense of security because it might lead to neglecting fundamental hygiene measures, such as proper hand hygiene.

There are also arguments in favour of using face mask at community settings. Respiratory droplets - which are considered to be the main way of coronavirus spread - are generally thought to travel short distances before falling onto surfaces near to the person who released them.

But researchers at Massachusetts Institute of Technology (MIT), using high-speed cameras and other sensors found that, in laboratory conditions, coughs and sneezes may project particles much further into the air than previously thought - six metres for a cough and up to eight metres for a sneeze. Evidence suggests Covid-19 could be transmitted before symptom onset and community transmission might be reduced if everyone, including people who have been infected but are asymptomatic and contagious, wear face masks. It would also be rational to recommend that people in quarantine wear face masks if they need to leave home for any reason, to prevent potential asymptomatic or pre-symptomatic transmission. Furthermore, it would be reasonable to suggest the most vulnerable populations in communities who are more susceptible to infection and mortality, if infected, including older adults (particularly those older than 65 years) and people with underlying health conditions, avoid crowded areas and use surgical face masks when exposed to high-risk areas.

Dr Tedros Adhanom Ghebreyesus, the Director General of WHO, has said "WHO continues to gather all available evidence and continues to evaluate the potential use of masks more broadly to control Covid-19 transmission at the community level,"

The World Health Organisation (WHO) is opening up its discussion again looking at the new research from MIT and other institutions. The advisory panel is considering whether to suggest new guidance for the public on wearing face masks as a way to limit the spread of coronavirus. According to Professor David Heymann, chair of the advisory panel to the WHO, the new research may lead to change of the current WHO advice. He said that if the evidence is supported, then "it might be that wearing a mask is equally as effective as or more effective than distancing."

Prime Minister Sheikh Hasina has rightly and timely has given a directive to all government officials and employees to use masks while performing their duties. The directive came on April 02 for ensuring the personal protection of the government officials and employees from coronavirus infection and transmission. The Prime Minister also gave a 31-point directive for the nation on April 03. The 31-point directives include regularly following the health code including washing hands, using masks and maintaining social distance.

The global debate over the use of mask at the community settings should be resolved at the initiative of the World Health Orgnisation.


Dr Shah Mahfuzur Rahman, MBBS, Dip. Management, DPH, MSc, FRSPH, PhD, works at the Institute of Public Health, Dhaka.

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