Not all face masks effective in protecting against COVID-19, San Mateo County officials say

SAN JOSE, Calif (KTVU) - Weeks into the coronavirus crisis and there is a new concern facing people trying to avoid the spreading virus that centers on what they wear to cover their faces. Certain types of masks people wear as protection may do very little to stem the spread of COVID-19. 

Since March, masks have become the new must-have wardrobe item, designed to prevent the spread of the coronavirus. Various styles have flooded the market, from the N95 surgical masks to those designed for comfort.

“It’s super beneficial for someone like me because I wear glasses. And they fog up the glasses, and it impairs my vision," said construction worker Ryan McMann who was on the job Tuesday. Adding, "And this helps it where I can still wear the mask, but still see simultaneously."

According to San Mateo County officials, masks with valves or breathing ports in the front are not effective in limiting the potential spread of COVID-19. 

“People think you have something, and it protects you. But we have a responsibility, and I think that’s what the county health officer has tried to do, is to educate people that maybe, there’s a false sense of security,” said Supervisor David Canepa.

The San Mateo County Health Department in April penned an order that said a mask with a valve designed for easy breathing, “is not a face covering under this order and is not to be used to comply with this order’s requirements.”

“I’ve been talking about this now for about a month since I’ve been seeing people out on the street wearing these,” said Dr. Dean Winslow, a Stanford University medicine professor.

He said the same mask feature that makes it easier to breathe also makes it easier for droplets to escape and potentially spread the Coronavirus through a cough or sneeze.

“What the valve does is that it flops open and then it essentially allows a stream of air to flow out pretty much unobstructed,” said Winslow. “That obviates or bypasses the purpose of the mask, which is to protect other people from you aerosolizing particles that contain the virus.” Added Canepa, “We always have the right intension, but through this pandemic we’re constantly learning.”

San Mateo, San Francisco, Marin, and Alameda counties all have a similar restriction on masks with a valve. But that’s not the case in Santa Clara County, where officials say any covering is better than none at all.