Jan 11, 2022 - Health

Why we need to wear better masks

Data: Gholamhossein Bagheri and Eberhard Bodenschatz/Max Planck Institute; Chart: Will Chase and Annelise Capossela/Axios; Note: study examined FFP2 masks, which we denote as N95 here, given their similar performance.

With the Omicron variant causing infections to surge to record levels, masking is more important than ever — and increasing evidence indicates the quality of mask makes a significant difference.

The big picture: Fitted particle-filtering masks like N95s are up to 75 times more effective at preventing infection with COVID-19 than surgical masks, according to a study published recently in the Proceedings of the National Academy of Sciences.

  • This echoes recent recommendations by public health experts about the value of N95 masks, reported by the Wall Street Journal.
  • It will take 25 hours for an infectious dose of COVID-19 to transmit between people wearing non-fit-tested N95 respirators but if they're wearing a tightly sealed N95, they'll have 2,500 hours of protection, per a study reported by the WSJ.

The details: In the recent study by researchers at Max Planck Institute in Germany, they investigated the risk when two individuals are speaking with each other at a close distance. Their study used the most conservative estimates for simulations, meaning that any scenarios with a risk below 1% in their study can be assumed safe in a real-world environment.

  • As shown in the data visualization above, only universal masking with well-fitted N95 or similar masks reduced the risk to below 1% after 20 minutes.
  • Surgical masks and situations where one person wore a poorly fitting mask or did not mask reduced the infection risk to between 4-10% after 20 minutes, which is still far above the acceptable risk level, they said.
  • This study did not investigate cloth masks, but other studies have shown that they can provide even less protection than surgical masks.
  • A separate experiment from the study found that social distancing barely helped, with the infection risk reaching 80% after just one minute, and 99.9% after 20 minutes.

What they're saying: While the study was conducted before the presence of Omicron, these findings should hold up given the conservative estimates they used in their simulations, study authors Gholamhossein Bagheri and Eberhard Bodenschatz told Axios.

  • They recommend individuals buy an N95, KN95, or FFP2 mask that has a nose piece for adjustment.
  • The fit of the mask is the most important factor, Bodenschatz, said. “It turns out that leakage dominates over filtration.” Masks should have a tight fit around the face and nose to minimize any air leakage.

Between the lines: It's important to be on the lookout for true N95 or KN95 masks, meaning they are rated with a 95% filtration efficiency, as many counterfeits have flooded the market.

The bottom line: The difference in risk between universal and mixed masking behavior is huge.

  • “We were surprised how well universal masking can reduce the risk of infection, even with these extremely conservative estimates that we considered," Bodenschatz said. "If we wear masks well the virus will have a hard time. The risk of infection without masks is very high.”
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