Dispelling the myths: Face masks work to prevent COVID-19

Photo: The Ohio State University

COLUMBUS, Ohio–Since the COVID-19 outbreak began, misconceptions about the effectiveness of face masks have circulated.

Today, uncertainties about face coverings still exist, but Sanja Ilic, associate professor and food safety state specialist with Ohio State University Extension, is translating her research and educating the community about how masks can prevent the virus spread. OSU Extension is the outreach arm of The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES).

Through a series of simple home experiments, anyone, including students in grades K-12, can test if their mask stops COVID-19.

“These tests,” Ilic said, “demonstrate the droplet transmission and serve as an educational tool of how the viruses are transmitted and how we can prevent them in the community.”

In early March of 2020, Ilic and her colleagues at Case Western Reserve University performed experiments to test the effectiveness of face coverings made from household fabrics. During an interview, she discussed their results and explained how the public can test the safety of their own mask fabrics and share their findings with others on a dedicated website.

Here, Ilic answers some questions about her new project.

Q: Why did you decide to do this experiment?

A: Early on during the pandemic, the official recommendation was not to wear masks, and the community was under the impression that masks were not necessary or effective in preventing the transmission of virus. While we knew that surgical masks were effective, we decided to test face coverings made from household fabrics and see whether these would be as effective in preventing the transmission.

Q: How did your experiment work?

A: We used a simple model designed to simulate the droplets that transmit the virus. We used a spray bottle filled with saliva-like liquids containing microorganisms and simulated a sneeze, and then measured the distance that the droplets flew without any barrier.

The large infectious droplets traveled up to six feet, while small droplets dispersed as a cloud and could travel longer distances.

We then tested fabrics to assess how effective they were in preventing droplet transmission. We tested fabrics that can be readily found in households, including cotton used for t-shirts and pillowcases, and other polyester materials like the ones for sports jerseys.

Q: Did the homemade textiles work to prevent transmission?

A: Yes, every fabric that we tested showed a major reduction in droplet transmission and with them, the microorganisms.

The most effective fabric was double-layered cotton, which was similarly as effective as surgical masks, preventing almost all infectious droplets.

The least effective masks were single layered polyester, preventing 97.2% of infectious droplets.

Q: How reflective are the lab results to what happens in real-life transmission of COVID-19?

A: We modeled the transmission of the droplets and know how far droplets can travel after they are expelled from a person that sneezes or coughs. A number of studies conducted by other groups have shown similar droplet transmission patterns. Our experiments show that the fabric is an effective barrier to prevent the droplet transmission.

However, the face masks made of these fabrics are only effective in preventing the transmission if they are worn properly, completely covering the nose and mouth of a person that is wearing them.

Q: Why is this experiment important to educate students and the general public about whether masks prevent the spread of COVID-19?

A: During the pandemic, community-based interventions, such a face masks, can save lives. We would like the community to understand the reasons and principles behind the recommendations to wear the mask.

Q: How did you translate this experiment into an educational module for K-12 students?

A: We have developed two educational modules based on this experiment. Firstly, working with a group from Kent University, Case Western and others, we designed a set of four activities, including the experiment that students can perform with the help of educators in schools or at home.

The activities are designed to demonstrate the droplet transmission and the effectiveness of the textile covers in preventing the transmission. The complexity of activities increases gradually.

The students can benefit from the experiments by learning about mask safety and how the virus is transmitted. Older students can also practice their STEM skills through the advanced activities. The modules are translated in four languages: English, Spanish, Portuguese and French.

In addition, I have worked with Associate Professor Tiffany Wild to develop an education module for visually impaired and blind students. This module includes general information about COVID-19, a 3D model of the virus and a set of four activities adapted for students with visual impairments. This is the first educational piece about COVID that was developed in the U.S. for visually impaired and blind people.

Q: What is one thing you would like people to know about COVID-19?

A: I want to clarify how the virus is transmitted, both directly and indirectly. The most common form of transmission is through direct contact when the large droplets travel directly from one person to another.

Indirect transmission, also known as fomite transmission, occurs when people touch contaminated surfaces and breath in the droplets. This transmission is not as common, but it still happens, which is why it is important to frequently sanitize surfaces, wash your hands and avoid touching your face.

The strategies are most effective when everyone is doing them.

The masks play an important role in both forms of transmission: preventing the virus from passing from one person to another as well as keeping people from touching their mouths and noses.

Even with the vaccinations underway, face masks and distancing are still required to prevent the transmission of COVID-19.

* Editor's note: Sanja Ilic will present a seminar on the “Effectiveness of Facemasks and Factors Associated with Prevention of Infections,” Feb. 12 from 11:30 a.m. to 1:20 p.m. To view the seminar on Zoom, go to https://osu.zoom.us/j/97021537043?pwd=QzRoek1WdEJsSWx5SG5xTjNoSjdQQT09. The meeting ID is: 970 2153 7043. The password is: 6v826f.

CFAES News Team
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Sanja Ilic