5 Evidence-Based Reasons for Wearing a Mask to Limit Spread of COVID-19

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After months of lockdown interventions, mixed messages from authorities, politicizing and questionable advice mushrooming on social media, the public is increasingly suffering from “COVID-19 fatigue”. One of the consequences is that many people are letting their guard down and no longer following the simple public health guidelines that will help to contain the spread of the virus: universal masking in public spaces and social distancing.

The initial advice was that wearing a cloth mask in public would not make a difference. However, since those early days of the pandemic, there has been more-and-more evidence that non-medical masks can have a significant impact on containing community transmission and even reducing the severity of the disease when people do become infected. And the more people who wear masks, the better!

As a result of growing evidence, official guidelines were changed. Recently, national organizations representing health professionals issued an open letter encouraging the public to continue masking, social distancing, and sanitizing. The voice of trusted professionals matters in this era of confusion.

In this article, we outline some evidence in support of universal masking that you can use while educating others about why they need to wear a mask in public.

1. The virus is spread by droplets and aerosols

Initially, it was thought that the SARS-CoV-2 virus was transmitted mainly via large droplets expelled forcefully by, for example, coughing and sneezing. With large droplets, which fall rapidly, people become infected during direct contact with others or indirectly through contact with surfaces on which the droplets have settled.

Evidence is now mounting that the virus may also be transmitted through aerosols – smaller droplets expelled even during normal breathing and speaking. Aerosol droplets evaporate rapidly, remain in the air for a long time, and carried by air currents over a long distance. This means that people can become infected by inhaling the airborne virus particles, which can accumulate in high concentrations, especially in crowded and poorly ventilated indoor areas.

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Masks, even those made from fabrics, create a barrier. They help contain the spread of droplets by infected individuals, and they also reduce the chance of others inhaling the viral particles.

2. Those who don’t have symptoms can spread the virus

Individuals infected with COVID-19 have a high viral load in their nose and throat in the days before symptoms develop or are asymptomatic. It now appears that this is when the infection is the most contagious. After someone is infected, it takes an average of 5-10 days to develop symptoms, and according to various studies, it seems that around 40-45% of infected individuals never develop symptoms.

This means that we really don’t know who might be spreading the virus in public spaces – silently and unknowingly. Public health experts are concluding that community transmission – defined as each infected individual infecting more than one other person – is being driven mostly by those who are asymptomatic or pre-symptomatic. This can be contained by universal masking.

3. Cloth masks can block aerosols and droplets

In one study, researchers tested the effectiveness of various fabrics from which cloth masks are commonly made. They found that combining different fabrics in two layers could provide up to 90% protection against aerosol particles – similar to surgical masks. However, when masks didn’t fit properly, the filtration’s effectiveness was reduced by up to 60%.

The evidence from laboratory testing shows that cloth masks can be effective in blocking droplets from the source and protecting uninfected people from inhaling them. While no mask can block viral transmission completely, well-made cloth masks are a simple and efficient public health measure to limit the transmission of COVID-19.

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4. Epidemiological data support the effectiveness of masks

Laboratory findings do not necessarily translate to real-life situations, but epidemiological data from around the world further supports the effectiveness of widespread masking to reduce community transmission.

In a number of countries, including Japan, Hong Kong, Taiwan, Thailand, Singapore and South Korea, wearing a mask had become culturally acceptable since the SARS pandemic of 2003. Widespread masking was adopted in these countries early on in the COVID-19 pandemic, and they have had considerably lower rates of infection, severe prognosis, and deaths.

There have also been a number of “case studies” in various locations that reinforce that wearing masks limits viral transmission. The best known is probably the case that occurred in Springfield, Missouri, where masking was only mandatory in personal care shops. Two hairstylists tested positive after, between them, they had close contact for around 30 minutes at a time with 140 clients. The authorities expected a surge in cases, but not one of these contacts, colleagues, or other clients at the salon tested positive or became ill – everyone had worn a mask.

5. Viral dose potentially affects the severity of infection

Epidemiological observations also support a further theory that is gaining increasing backing from health experts – the number of virus particles a person breathes in could determine the severity of the disease.

One of the case studies supporting this theory was that of passengers and crew on a cruise ship where everyone was provided with masks. Among those who became infected, 81% were asymptomatic.

This implies that with universal masking, an individual who becomes infected will probably have gotten a smaller dose of the virus and is likely to experience milder symptoms or be asymptomatic. This is because masking reduces the viral load in the environment and the mask filters out most of the viral particles.

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Universal Masking could turn the tide of COVID-19.

Masks are not 100% effective in preventing transmission of SARS-CoV-2 – but neither will wearing a seatbelt prevent all injuries in car accidents – it’s about significantly reducing the risks. Based on mounting evidence, experts now believe that if 80% or more people wore masks while in public, it could halt community transmission.

Wearing a mask is not a political choice – protecting each other is the ethical and responsible thing to do. 

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Frieda Paton is a registered nurse with a Master’s degree in nursing education. Her passion for nursing education, nursing issues and advocacy for the profession were ignited while she worked as an education officer, and later editor, at a national nurses’ association. This passion, together with interest in health and wellness education since her student days, stayed with her throughout her further career as a nurse educator and occupational health nurse. Having reached retirement age, she continues to contribute to the profession as a full-time freelance writer. In the news and feature articles she writes for Nurseslabs, she hopes to inspire nursing students and nurses on the job to reflect on the trends and issues that affect their profession and communities - and play their part in advocacy wherever they find themselves.

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