As we all know by now, one of the most simplest yet effective methods to prevent the spread of COVID-19 is to wear a mask. However, in a recently updated guidance, the Centers for Disease Control and Prevention (CDC) warned against wearing masks with exhalation valves or vents because such masks do not prevent the person wearing the mask from transmitting COVID-19 to others.
COVID-19 is mainly spread through respiratory droplets. People who have COVID-19 can spread respiratory droplets when they cough, sneeze, talk, or raise their voices. As such, the CDC recommends masks as a simple barrier to prevent respiratory droplets, this is called source control. This recommendation is based on what scientists know about the role respiratory droplets play in the spread of COVID-19, as well as evidence from clinical and laboratory studies that shows masks reduce the spray of such droplets when worn over the nose and mouth. Because COVID-19 spreads among people who are in direct or close contact with each other, the use of masks is crucial when people are not able to social distance.
Among the various types of masks, the CDC does not recommend the general public wear N95 respirators as they are intended for healthcare workers right now. However, the CDC also does not recommend N95 respirators with valves or vents because they do not prevent the exhaled respiratory droplets from potentially spreading COVID-19.
The purpose of wearing a mask is to keep respiratory droplets from reaching others to aid with source control.
“However, masks with one-way valves or vents allow air to be exhaled through a hole in the material, which can result in expelled respiratory droplets that can reach others,” the CDC’sw guidance reads. “This type of mask does not prevent the person wearing the mask from transmitting COVID-19 to others. “Therefore, CDC does not recommend using masks for source control if they have an exhalation valve or vent.”
Based on the updated CDC guidance, masks with valves have been banned by major U.S. airlines, such as American Airlines.
As many people with COVID-19 do not have any symptoms, the CDC recommends all people 2 years of age and older to wear a mask in public settings and when around people who do not live in your household.