Scientists reveal the best and worst face masks to use for COVID-19 protection

By Angela Betsaida B. Laguipo, BSNAug 10 2020

The coronavirus pandemic is far from over, as the number of reported infections tops 20 million globally. The coronavirus disease (COVID-19), which has emerged in December 2019 in China, has now spread across 188 countries and territories, taking more than 733,000 lives. Since the advent of the pandemic, health experts have recommended wearing face masks to reduce the risk of infection.

Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 disease can spread through respiratory droplets when a person coughs, sneezes, or talks. However, using face masks can significantly reduce the risk of SARS-CoV-2 virus transmission. As the pandemic grew, the supply of surgical and medical masks was markedly depleted. Subsequently, health organizations recommended using handmade masks.

With that in mind, scientists at Duke University went about testing 14 different types of masks to determine which offers the best protection against SARS-CoV-2 infection. The team has found that bandannas, gaiters, and knitted masks are some of the least effective face coverings for preventing the spread of SARS-CoV-2.

Study: Low-cost measurement of facemask efficacy for filtering expelled droplets during speech. Image Credit: Woottisak / Shutterstock

Testing masks

The team conducted a proof-of-concept study, which was published in the journal Science Advances, wherein they revealed that the simple, low-cost technique provided visual proof that face masks are effective in reducing droplet emissions during normal wear.

“We confirmed that when people speak, small droplets get expelled, so the disease can be spread by talking, without coughing or sneezing. We could also see that some face coverings performed much better than others in blocking expelled particles,” Martin Fischer, a chemist, and physicist explained.

While mask alternatives, such as bandannas and neck fleece, offer very little protection against COVID-19 transmission, N95 masks, which are often used by healthcare professionals, worked best to stop the transmission of respiratory droplets during regular speech.

Some of the best masks include three-layer surgical masks and cotton masks, which can be made at home, the researchers said.

“We compared a variety of commonly available mask types and observed that some mask types approach the performance of standard surgical masks, while some mask alternatives, such as neck fleece or bandanas, offer very little protection. Our measurement setup is inexpensive and can be built and operated by non-experts, allowing for rapid evaluation of mask performance during speech, sneezing, or coughing,” the researchers concluded.

Importance of wearing masks

According to the researchers, more research is needed to identify variations of results depending on the masks used, speakers, and how people wear them. However, the study provides an idea for companies on how to conduct mask testing to determine which masks are best for employees.

The team also emphasized that wearing a mask is a simple yet effective way to stem the spread of COVID-19. If everyone wore a mask, 99 percent of the respiratory droplets could be stopped before they reach another person.

This is essential since as many as 40 percent of infected people do not know they carry the virus and can transmit the virus to equally unsuspecting people. Wearing a mask by everyone can reduce the chance of asymptomatic transmission, wherein people who do not feel sick are infected with the virus. If they mingle with other people, there is a high chance they can transmit the dreaded virus.

Since as many as 40% of infected people don’t actually know they have the infection and therefore transmit the novel coronavirus to equally unsuspecting people they come in contact with, “knowing what does and does not stop transmission is critical, the researchers said. So is wearing a mask”.

“Wearing a mask is a simple and easy way to reduce the spread of COVID-19. About half of infections are from people who don’t show symptoms, and often don’t know they’re infected. They can unknowingly spread the virus when they cough, sneeze and just talk,” Dr. Eric Westman, a Duke physician, said.

“If everyone wore a mask, we could stop up to 99% of these droplets before they reach someone else,” Westman said. “In the absence of a vaccine or antiviral medicine, it’s the one proven way to protect others as well as yourself,” he added.