Face masks with valves or vents don’t help prevent spread of coronavirus, CDC warns

Not all face masks are created equal when it comes to curbing the spread of the coronavirus, the U.S. Centers for Disease Control and Prevention says.

In an updated guide on face masks, the agency notes that masks with valves or vents do little to prevent an infected person from potentially spreading the virus to others.

“The purpose of masks is to keep respiratory droplets from reaching others to aid with source control,” according to the CDC.

“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 agency noted.

“Therefore, CDC does not recommend using masks for source control if they have an exhalation valve or vent,” the revised guide reads.

The guide doesn’t address whether such masks can help protect the wearer against airborne viruses, saying the primary purpose of masks during the pandemic is to protect others.

And the CDC still advises the general public against wearing surgical masks or N95 respirators, which it says should be reserved for medical personnel.

This story was originally published August 13, 2020 at 10:52 AM with the headline "Face masks with valves or vents don’t help prevent spread of coronavirus, CDC warns."