A leading expert in infectious diseases said Sunday that wearing more than one face mask could actually increase the chance of getting sick, countering the advice of some experts published last week.
Michael Osterholm is the director of the Center for Infectious Disease Research and Policy at the University of Minnesota and served on President Joe Biden's COVID-19 Advisory Board during his transition. He warned of the complications that two masks could cause, namely the elimination of airflow that is necessary to properly filter viral particles.
"When we talk about double masking, remember what we're really talking about is just trying to prevent the virus from being excreted by me into the air or me inhaling the virus from someone else in the air, and it's both a function of face fit and face filtration," said Osterholm.
Osterholm said that a mask should prevent air from leaking around the sides, comparing them to swim goggles.
"What we're concerned about is that many of these face cloth coverings do have already compromised fit or filtration capacity," he said. "If you add on another mask, you may actually make it tougher for the air to move through the two-cloth area, and then at that point, it causes more air to actually leak around the sides, which actually enhances your ability to get infected."
Osterholm also noted that a large percentage of the population does not currently wear masks correctly and that adding a second mask in such situations is "like fixing three of the five screen doors in your submarine."
Biden chief medial adviser Dr. Anthony Fauci and other experts, including virus expert Linsey Marr of Virginia Tech, indicated last week that two masks should become the norm.
"If you have a physical covering with one layer, you put another layer on it; just makes common sense that it likely would be more effective," said Fauci at the time.