CDC is bowing to reality and grudgingly giving their blessing to civilian use of over-the-counter respirators ("masks" in common parlance) should there be an influenza pandemic. I've repeatedly called attention to the lack of evidence that wearing a respirator would be effective to protect people from influenza virus. Many readers here (mistakenly) believe I am against masks. I am not. Nor am I for them. If this is a pandemic Pascal's wager -- it can't hurt and maybe it will help -- that's fine. As long as the premise -- that it can't hurt -- is true. That's my main reason for wanting some reasonable appraisal of efficacy.
From the CDC "guidance":
There is very little research about the value of masks to protect people in public settings. These interim recommendations are based on the best judgment of public health experts who relied in part on information about the protective value of masks in healthcare facilities.[snip]
The guidance stresses that during an influenza pandemic a combination of actions will be needed, including hand washing, minimizing the likelihood of exposure by distancing people who are infected or likely to be infected with influenza away from others and treating them with antiviral medications, having people who are caring for ill family members voluntarily stay home, and encouraging people to avoid crowded places and large gatherings. When used in conjunction with such preventive steps, masks and respirators may help prevent some spread of influenza.
[snip]
"During an influenza pandemic, we know that no single action will provide complete protection," said Dr. Julie Gerberding, CDC director. "We also know that many people may choose to use masks for an extra margin of protection even if there is no proof of their effectiveness. If people are not able to avoid crowded places, large gatherings or are caring for people who are ill, using a facemask or a respirator correctly and consistently could help protect people and reduce the spread of pandemic influenza." (CDC Press Release)
In other words, "If you are going to use one anyway, we can't say it's wrong. But you better do all the other things, too."
Here is the actual "guidance" part:
- People should consider wearing a facemask [CDC terminology for a surgical mask] during an influenza pandemic if --
They are sick with the flu and think they might have close contact with other people (within about 6 feet). They live with someone who has the flu symptoms (and therefore might be in the early stages of infection) or will be spending time in a crowded public place and thus may be in close contact with infected people. During a pandemic, people should limit the amount of time they spend in crowded places and consider wearing a facemask while they are there.
- They are well and do not expect to be in close contact with a sick person but need to be in a crowded place. Again, people should limit the amount of time they spend in crowded places and wear a facemask while they are there.
- People should consider wearing a respirator during an influenza pandemic if --
They are well and will be, or expect to be, in close contact (within about 6 feet) with people who are known or thought to be sick with pandemic flu. People should limit the amount of time they are in close contact with these people and wear a respirator during this time. These recommendations apply if people are taking care of a sick person at home (and if a respirator is unavailable, use of a mask should be considered).
Still, what's the harm? The fly in the ointment is that some people might wear masks thinking they will protect them and venture into crowds or take less care with people who have symptoms or even infect themselves by reusing or touching the outside of a contaminated mask or fail to wear a properly fitted one or . . . .
Given these possibilities, calling attention to the fact we know little about the efficacy of masks doesn't seem unreasonable to me.
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I thought masks protect the patient from the medical staff. During a flu pandemic, masks should protect everyone else from the wearer. If 'everyone else' is a wearer too, because almost everyone wears a mask in public, the protection won't be 100%, but neither are seat belts, and we're all supposed to wear those.
As to contamination during removal, logic says inhaling should move viral particles toward the lungs. If there are viral particles on the mask, it's because the mask *stopped* those particles from going into the lungs. Some viruses might be transferred from there to somewhere they can cause infection, but it would be harder than if they'd been inhaled in the first place.
If there is concern that people won't use masks correctly, I vote for education. Cartoon drawings of nasty virus characters jumping from the mask to fingers, then getting washed down the drain with soap and water? Printed on the mask box? Works for me!
Of course it's hard to eat at a restaurant with a mask on....but by the time everyone is willing to wear a mask in public, I doubt many people will want to eat out. My grandmother spoke of seeing people looking healthy one morning, and hearing they'd died the next.
I just want people (and hospitals) to start buying masks (among other essential supplies) NOW, while there's still time to ramp up production.
ipmat: surgical masks might be good for protecting others from a cougher, but the guidance is for the general public to use "in the community." The question of virus on the mask or respirator is the qustion ofhandling it and getting it on your hands, etc. Education isn't the answer to proer fit. To really protect someone against respirable particles, a mask has to be fit by those who do this professionally. Submicron particles pass through just about anythning. Leaking around respirators is extremely common in use by professionals. It isn't just a matter of instructions or a diagram. And as for protecting you outside, well, it probably doesn't because you wouldn't get infected outdoors anyway. On the subway? Who knows. Maybe yes, maybe no.
To really protect someone against respirable particles, a mask has to be fit by those who do this professionally.
Sure. And once that's done, there is a near 100% level of protection.
What I have voiced in the past is that cheap masks used by persons with cursory training won't provide anything near to 100% protection. But suppose those masks afford only 30% protection. In a pandemic, would 30% fewer infections not be welcome? In a system where there will be acute shortages of medical resources for those who are ill?
I am glad to see that CDC has figured out the idea that surgical masks should be worn by those who are unwell. The design of such masks is intended to capture and filter exhalations.
Those who are well should wear (at a bare minimum) a reputable N95 mask. But CDC should stress that those who are sick should not wear these! A good N95 or higher unit will have an exhalation valve on it, which aids creatly in maintaining a reliable face seal and in ensuring compliance (masks without valves get uncomfortable much more rapidly).
But for someone who is ill and infectious, that valve would be a direct unfiltered conduit to the outside air. Bad news.
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In an epidemic I might conceivably wear one as a behavioral modification device. A mask would be a good reminder to me not to touch my mouth or nose, and to wash my hands before taking the mask off. It also might signal others to keep their distance from me.
Any comments on the Nanomask?
I am with you guys ipmat and marquer and especially the decrepitoldfool on this -- Revere's purism is off beam for once, he/she is looking at the technical detail - the trees, not the woods.
I for one would like to see the first act of enforcement to be the mandatory requirement to use some form of facial mask in any public place, and for that requirement to be enforced until the pandemic was officially declared as over. We might be the brightest creature on the planet, but the majority of us are still as thick as two short planks and getting the message over that the 'buggey man' is amongst us requires a pretty graphic alert. During the war the air raid sirens did not mean that a bomb was about to drop on you, it meant that we all had to modify our behavior because the risk of a bomb dropping on you had now gone up significantly and for a while we had to live in a modified and safer way. The intention would be for the masks to act as behavioral modification device for the whole of society.
The second 'real' reason for wearing masks is to remind us to stop picking/scratching our noses and chewing our nails. Humans are creatures of touch, we use our hands for just about everything. Yes we will be at risk of breathing in the virus, but stand quietly for a while and watch your fellow humans -- watch their hands and how often they touch objects and touch their faces -- it is a non stop dance of the hands and in the face of a pandemic, the hands will be collecting viral particles from a multitude of surfaces (even when the airborne load is gone) and transporting them to the eyes, nose and mouth. Yes we will need to stress the need to wash hands regularly, but between washings we need to stress the need to keep the fingers out of the nose, and a face covering is a simple and constant reminder.
Finally, never forget that a pandemic is simply the movement of the Ro from below 1.0 to above 1.0 Anything, no matter how tiny or weakly effectual that manages to reduce the Ro back below 1.0 can effectively snub out the pandemic. The BUT however, is that the intervention has to be implemented by everyone and the statutory requirement to wear face protection in public could well be one of those tipping points. Of course, there is another BUT, and that is that there will not be anywhere near enough face masks available unless governments start to get the public to sock up with them now.