Little Evidence Supports Use of Cloth Masks to Limit Spread of Coronavirus: Analysis
BY
ZACHARY STIEBER November 15, 2021 Updated: November 15, 2021
“The remainder of the available clinical evidence is primarily limited to non-randomized observational data, which are subject to confounding,” the researchers said, including accounting for other differences in behavior among those who don’t wear masks.
They did say that there is evidence masks reduce droplet dispersion, though cloth masks are unlikely to capture the particles even if worn properly.
Due to the COVID-19 pandemic, policymakers cannot wait for higher-quality evidence to support masking, but from an ethical standpoint, they should “refrain from portraying the evidence as stronger than it actually is,” the researchers concluded.
COVID-19 is the disease caused by the
CCP (Chinese Communist Party) virus. The CCP virus is also known as the coronavirus, or SARS-CoV-2.
Some outside experts’ views align with the researchers, including Dr. Martin Kulldorff, senior scientific director of the Brownstone Institute.
“The truth is that there has been only two randomized trials of masks for COVID. One was in Denmark, which showed that they might be slightly beneficial, they might be slightly harmful, we don’t really know—the confidence interval kind of crossed zero,” he said. “And then there was another study from Bangladesh where they randomized villagers to masks or no masks. And the efficacy of the masks was for reduction of COVID was something between zero and 18 percent. So either no effect or very minuscule effect.”
Some experts, though, say the existing evidence does support masking recommendations, and several reacted strongly to the new analysis.
The analysis drew some pushback, including from Kimberly Prather, director of the National Science Foundation Center for Aerosol Impacts on Chemistry of the Environment.
Prather noted on Twitter that researchers said masks reduce the amount of virus in the air and believed that ran counter to their conclusions.
Darrow responded by saying the amount of virus in the air was a surrogate, not a clinical endpoint.
“The amount of pathogen in air (to be inhaled) directly determines the dose. This is directly linked to risk,” Prather added. “Or can you explain how less virus in the air could be higher risk? It’s equivalent to saying that less pathogen in drinking water is higher risk so don’t filter water.”
“If the theory diverges from what you see in real life, which one do you believe?” Darrow said.