Are face masks effective against coronavirus disease?

by Fanila Shahzad and Talat Nasim | Published: 00:00, Apr 07,2020

 
 

THE new Coronavirus now labelled as COVID-19 has become a global pandemic affecting 201 countries. In order to slow down the spread of the virus, health authorities have implemented various degrees of governmental lockdowns as seen in countries such as India, China, France, Pakistan, the UK and Bangladesh and have also emphasised the process of maintaining good personal hygiene by washing hands thoroughly and using face masks. However, the use of face masks has led to some controversy which raises the question whether or not face masks are effective against the new coronavirus.

Face mask is a device which produces a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. There are typically two types of face masks, N95 respirators and surgical masks. Both masks are made from polypropylene; however key differences exist between them. The N95 respirator is a tight-fitting mask that has the ability to filter out 95 per cent of droplets smaller than 0.3 micrometre; whereas, surgical masks are loose fitting, disposable masks that are typically used to protect the wearer from large particle droplets. There is also a third unconventional type of mask as people have begun to make their own masks from various materials in response to the urgent need for masks in the COVID-19 pandemic. The use of face masks has become universal in China and South Korea, with some areas in China enforcing regulations regarding the compulsory use of face masks in public areas. Despite this, the universal use of the face mask in the community has been discouraged with the notion that they provide no effective protection against the new coronavirus. For example, according to the World Health Organisation, ‘you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection’. However, as evidence suggests, COVID -19 can be transmitted before even the symptoms are visible, and, therefore, advising only people with symptoms to wear masks will not stop the spread of the disease. Thus, it can be assumed that these recommendations were not stemmed from scientific evidence but were motivated to discourage widespread use of face masks in order to preserve limited supplies for professional use in healthcare settings.

A study conducted in 2008 by Van Der Sande looked at the transmission reduction potential provided by surgical masks, homemade masks and personal respirators and found that there was a decrease in viral exposure and infection risk, regardless of the type of masks. There are many other studies which support this notion. For example, a randomised clinical trial reported that standard surgical masks are as effective as personal respirators for preventing infection of healthcare workers in outbreaks of viral respiratory illnesses such as influenza. Similar results were also found in a recent study looking at the association between COVID-19 transmission and N95 respirator use.  Additionally, a study conducted in 2013 examined homemade masks as an alternative to commercial face masks and found that despite commercial surgical masks being three times more effective in blocking transmission, homemade masks made from cotton were still effective in reducing the number of microorganisms expelled from volunteers, something which is vital to limit the spread of this current pandemic. Thus, it can be suggested that masks do not need to be complex to be effective and any kind of mask is better than no protection.  Homemade masks made out of cotton T-shirts can therefore overcome the shortage of manufactured masks, allowing front line health workers to protect themselves with appropriate personal protective equipment.

However, cautions should be taken if people start wearing face masks in public as there is a danger of further viral transmissions if masks are not worn appropriately. Masks should not be worn more than once and should be discarded when they become damp or moist. Individuals should follow the current WHO guidelines in order to prevent a contaminated mask from spreading infection.

Community use of masks alone may not be enough to completely stop the spread of infection though. Given the weight of the evidence, it seems likely that community transmission of COVID-19 may be reduced if everyone, including asymptomatic carriers and contagious patients, wear face mask appropriately.

 

Fanila Shahzad is an honorary visiting researcher working under the supervision of Dr Talat Nasim, a Bangladeshi born British scientist. Both authors work in the area of translational medicine at the University of Bradford, UK. 

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