EXPLAINED: Efficiency of Different Types of Face Masks in Preventing COVID-19

There would be hardly any household in the world that would be oblivious to the use of facemasks since the past few years. Governments across the world have urged their citizens to use facemasks in public. Some countries have also enforced strict laws and have mandated the use of facemasks. With different varieties of facemasks available in the market, one would wonder which variety of mask is more effective in stopping the deadly virus. There have been several instances where social media users have shared misleading information about efficiency of various types of facemasks. So how effective are these facemasks? Which variety of mask provides maximum protection from COVID-19? Let us study and understand from what experts have to say.

How Effective are Masks in protection against Covid-19 infection?

The Novel Coronavirus Disease 2019 (COVID-19): Guidelines on rational use of Personal Protective Equipment states “Respiratory viruses that includes Coronaviruses target mainly the upper and lower respiratory tracts. Hence protecting the airway from the particulate matter generated by droplets / aerosols prevents human infection. Contamination of mucous membranes of the mouth and nose by infective droplets or through a contaminated hand also allows the virus to enter the host. Hence the droplet precautions/airborne precautions using masks are crucial while dealing with a suspect or confirmed case of COVID-19/performing aerosol generating procedures.”

A study titled “Face masks, public policies and slowing the spread of COVID-19: Evidence from Canada,” published in the Journal, Science Direct, in July 2021, states “mask mandates are associated with a 22 percent weekly reduction in new COVID-19 cases, relative to the trend in absence of mandate.”

A discussion paper titled “Face Masks Considerably Reduce COVID-19 Cases in Germany:

A Synthetic Control Method Approach,” published in June 2020 by the IZA Institute of Labour Economics, states:  “Depending on the region we analyse, we find that face masks reduced the cumulative number of registered Covid-19 cases between 2.3% and 13% over a period of 10 days after they became compulsory. Assessing the credibility of the various estimates, we conclude that face masks reduce the daily growth rate of reported infections by around 40%.”

The World Health Organisation or WHO website states that masks should be used as part of a comprehensive strategy of measures to suppress transmission and save lives; the use of a mask alone is not sufficient to provide an adequate level of protection against COVID-19.

WHO suggests that wearing of a mask should be made a normal part of being around other people. The appropriate use, storage and cleaning or disposal of masks are essential to make them as effective as possible. Thus, even though the mask cannot provide complete protection but still WHO suggests it should be made a new normal as it helps to supress transmission of COVID-19.

Is usage of Masks enough to protect against infection?

An article titled “Face mask – An essential armour in the fight of India against COVID-19,” published in the Indian Medical Journal in February, 2021 states that wearing a mask is not an alternative to physical distancing and hand hygiene, but it is most valuable in scenarios where physical distancing is challenging. Face masks limit the spread of infectious respiratory droplets into the environment. 

Types of Masks:

There are three types of face masks available in the market: cloth masks, respirator masks (N95), and surgical masks. 

The first kind- Cloth masks are usually made of cotton fabric and have been widely used during the pandemic as they are easily available and are not expensive. Despite some cloth masks having two or three layers, they are porous and hence not well equipped to filter out the tiny particles that may infect the user. They are washable and durable. They are best used as an additional mask with the recommended N95 mask. 

Now, the question that arises here is, why were we told to wear cloth masks at first?

An article titled “Time to upgrade from cloth and surgical masks to respirators? Your questions answered,” published in the journal The Conversation on January 17, 2022, answers this question. It states “It was initially assumed SARS-CoV-2 spread via droplets (in coughs and sneezes) which caused infection when they landed on the mouth, nose or eyes. For such particles, a cloth or surgical mask is an efficient form of source control to protect others from virus emitted by the wearer.

Now it’s understood the virus is airborne. Virus-laden particles build up in the air over time indoors because of breathing and speaking.”

Certified N95 masks are equipped to filter out 95% of air particles and hence are touted for maximum safety from Covid-19 infection. Despite being multi layered, these masks are breathable. They are available in different sizes and if the fit is perfect, it wraps snugly around the nose and mouth area, offering protection against any droplets or particles in the air. 

However, N95 masks with respirator valve should be avoided, as it does not provide protection from the virus. The Director General of Health Services (DGHS) of Indian Health Ministry, Rajeev Garg says in a letter to all the states and Union territories, “that the use of valved respirator N-95 masks is detrimental to the measures adopted for preventing the spread of coronavirus as it does not prevent the virus from escaping out of the mask.”  

Surgical masks are made of breathable synthetic fabric and do not completely cover the nose and mouth area as they are loose fitting. An airtight seal is essential for protection from infection but such masks are not designed for it. They are however, recommended as an extra layer in a double mask for high protection as they are waterproof and might stop droplets from reaching the nose or mouth.

Here is a video by BBC’s Science Editor, published on February 2, 2021, examining the various kinds of masks:

How to select a Mask?

With the omicron variant spreading rapidly, CDC face mask guidance which is updated regularly, says N95 masks provide the highest level of protection, followed by KN95 masks, while loosely woven cloth masks provide the least amount of protection.

One should check the fit which must be snug, with no air circulation through the edges. 

As mentioned earlier, masks with vents or exhalation valves are not advised because they allow unfiltered breath to escape the mask. Such masks do not slow the spread of the disease as is proven by this video from the National Institute of Standards and Technology (NIST), USA. 

Centers for Disease Control and Prevention or CDC has listed a few points to keep in mind while choosing a mask:

Also, is especially important to ensure unvaccinated children or even adults use the kind of masks that are less porous and are recommended by the authorities.

Another important point to be kept in mind is that usage of any such mask is not recommended during rigorous physical activities. Maintaining distancing is recommended while exercising or undertaking any such rigorous activity. 

Do fully vaccinated people too need to wear a Mask?

The website of Mayo Clinic states that though one can return to leading a fairly normal activity routine like before the Pandemic, once vaccinated, however, if you are in an area with a high number of new COVID-19 cases, wearing a mask especially in crowded areas- whether outdoors or indoors or when you are in close contact with people is highly recommended. 

An article published in the Indian Medical Journal in February, 2021 states that although vaccinated individuals would have less risk of getting symptomatic SARS-CoV-2 disease, they may still be able to spread the virus to others and should therefore use face mask.