You don’t need to wear a face mask if you’re not sick: the Centers for Disease Control (CDC) says so.

But what if you’re sick and you don’t know it?

Er, well, . . .

As cases of the coronavirus continue to skyrocket, some of the nation’s top health officials are rethinking the benefits of wearing face masks to flatten the coronavirus curve: the CDC says it’s now reviewing its policy and may be considering a recommendation to encourage broader use.

On its website, the CDC says the only people who need to wear a face mask are those who are sick or are caring for someone who is sick and unable to wear a mask. And up until now they’ve been pretty specific about what to do if you’re not sick: “If you are NOT sick: You do not need to wear a facemask unless you are caring for someone who is sick (and they are not able to wear a facemask).”

The site goes on to say “Facemasks may be in short supply and they should be saved for caregivers.” Which is the thinking that’s guided most of the US population in recent weeks as, indeed, the nation faced a mounting shortage of facemasks.

But in an interview with NPR on Monday, CDC Director Robert Redfield said that the agency is taking another look at the data around mask use by the general public.

“One of the [pieces of] information that we have pretty much confirmed now is that a significant number of individuals that are infected actually remain asymptomatic. That may be as many as 25%,” Redfield told NPR. “That's important, because now you have individuals that may not have any symptoms that can contribute to transmission, and we have learned that in fact they do contribute to transmission.”

The data Redfield mentions includes data out of China, where a top health official was explicit about the need for facemasks to prevent the spread of COVID-19. George Gao, director-general of the Chinese Center for Disease Control and Prevention, told Science magazine “The big mistake in the US and Europe, in my opinion, is that people aren’t wearing masks.”

In particular, Gao said, wearing masks helps reduce the risk presented by people who may be infected but aren’t yet showing symptoms.

J. Scott Weese, DVM, DVSc, DACVIM, addressed the CDC’s position on face masks in an interview with NEWStat: “The CDC has been behind the curve a lot,” Weese said, especially as regards coronavirus concerns in the veterinary profession. However, Weese, contributing reviewer of AAHA’s Infection Control, Prevention, and Biosecurity Guidelines, doesn’t necessarily fault the agency: “I think they [had] other issues to deal with besides the animal side.”

As to the efficacy of masks, Weese anticipates what may well come to be the new official CDC view: “They’re not really designed to protect you. They’re more for the protection of people around you.”

Developing . . .

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