When the COVID-19 pandemic began in 2020, questions arose about the effectiveness of wearing a face mask to prevent the spread of the virus. Now, after three and a half years, what does the science say?
In an interview for 60 Minutes, Linsey Marr, a professor specializing in aerosol science at Virginia Tech University, was asked about the efficacy of masks by CBS News chief medical correspondent Dr. Jon LaPook.
“Masks are highly useful in reducing the risk of contracting COVID because they reduce the amount of virus inhaled from the surrounding air,” Marr stated.
No mask provides 100% protection. For example, N95 masks are named as such because they are at least 95% effective in blocking airborne particles when used correctly. However, even masks with an 80% efficiency can still offer significant protection,” Marr explained.
“This greatly reduces the risk of infection,” she added.
According to Marr, research has shown that high-quality masks can effectively block particles of the same size as those carrying the coronavirus. Masks function as filters, not sieves. Virus particles have to navigate through the layers of fibers, increasing the chance of collision and entrapment.
Marr used an analogy of running through a forest: Moving slowly allows easy navigation, but high-speed movement increases the likelihood of colliding with a tree.
“Even cloth masks have an impact,” she emphasized.
Can contaminated masks cause infection?
Early in the pandemic, there were concerns that wearing masks could lead to infection if a person encountered a contaminated mask and then touched their eyes, nose, or mouth. However, subsequent research has disproven this fear.
“There was no evidence to support that claim,” Marr clarified.
Marr’s team conducted a study where they aerosolized the coronavirus, pulled it through masks, and examined the amount of virus that remained on the masks. The study found that some viral particles remained on certain cloth masks, but no virus survived on N95 or surgical masks.
The team also conducted experiments where they touched artificial skin to the masks and evaluated the transfer of virus particles. No infectious virus was transferred.
“I hope this study reassures people that this concern is not as significant as we were led to believe,” Marr concluded.
The videos above were edited by Sarah Shafer Prediger.
