When the COVID-19 pandemic emerged in 2020, questions surrounding the effectiveness of wearing face masks to prevent virus transmission arose. Now, after three and a half years, what does science have to say on the matter? In a recent interview for 60 Minutes, CBS News chief medical correspondent Dr. Jon LaPook spoke with Linsey Marr, an aerosol science expert and professor at Virginia Tech University, to get some answers.
According to Marr, face masks are highly beneficial in reducing the risk of contracting COVID-19 as they minimize the amount of virus particles one would potentially inhale from the surrounding air. Although no mask can guarantee 100% effectiveness, masks like the N95, for instance, are named as such because they are at least 95% efficient in blocking airborne particles when used correctly. However, even masks with an 80% efficiency can still provide significant protection against the virus. Marr stressed that wearing a mask greatly decreases the chances of infection.
Marr explained that research shows high-quality masks have the ability to block particles of the same size as those carrying the coronavirus. Masks function as filters rather than sieves, as virus particles must navigate their way through multiple layers of fibers. In doing so, they may collide with these fibers and become trapped. Marr likened this process to running through a forest of trees; walking slowly allows for easy navigation, while being forced to move at high speed increases the likelihood of collision with a tree. “Even cloth masks serve a purpose,” Marr affirmed.
In the early stages of the pandemic, some health professionals suggested that wearing masks could actually lead to infection if someone came into contact with a contaminated mask and then touched their face. However, subsequent research has debunked this fear. Marr mentioned that her team conducted a study where they aerosolized the coronavirus, pulled it through different masks, and examined the amount of virus that remained on each mask. The study revealed that while some viral particles were still present on certain cloth masks, no virus survived on N95s or surgical masks. Additionally, the team conducted an experiment where they touched artificial skin to the masks to see how many virus particles transferred. No infectious virus was transferred in this case. Marr hopes that this study will alleviate concerns about the risk of contamination from masks.
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Please note that the above content has been edited by Sarah Shafer Prediger.
