# Face masks for flu prevention -- effective? **URL:** \ **Category:** Factual Questions\ **Created:** [April 27, 2009, 4:47pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516 "2009-04-27T16:47:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Jodi](https://avatars.discourse-cdn.com/v4/letter/j/7feea3/32.png) [@Jodi](https://boards.straightdope.com/u/Jodi)\ **Post date:** [April 27, 2009, 4:47pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/1 "2009-04-27T16:47:25Z")
The title says it all, really. Every time there’s a disease outbreak, we see all these pictures of people walking around in surgical masks. This time it’s concern over the swine flu. Recognizing that in some places such concern is warranted – does it really do anything to have on a surgical mask? I guess I’ve always assumed that a virus would go right through one. Or maybe the mask is not to protect the wearer from incoming germs, but to protect others from the wearer’s sneezing, coughing, etc.? That makes more sense, but I don’t get the feeling people are wearing them out of altruism, I assume that they wear them because they think the masks protect _them_. What’s the Straight Dope? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [April 27, 2009, 4:54pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/2 "2009-04-27T16:54:23Z")
The virus itself can almost certainly get through a mask. However, viruses are often attached to things - snot, water droplets, dust, etc. which could be trapped by the mask. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [April 27, 2009, 5:00pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/3 "2009-04-27T17:00:50Z")
> [@dracoi](#): > > The virus itself can almost certainly get through a mask. However, viruses are often attached to things - snot, water droplets, dust, etc. which could be trapped by the mask. And it seems like swine flu is probably transmitted similarly to standard influenza (from what I’ve read so far), which is transmitted via droplets. So it’d protect your nose and mouth - not your eyes, which are still vulnerable - from flying droplets from someone who sneezes/coughs without covering up sufficiently. You would also have to take care not to transmit the virus to yourself by touching anything contaminated (droplets on your clothing, from a doorknob, etc.) and then touching your eyes/nose/mouth. ---
**Author:** ![Claire\_Beauchamp](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@Claire\_Beauchamp](https://boards.straightdope.com/u/Claire_Beauchamp)\ **Post date:** [April 28, 2009, 3:30am UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/4 "2009-04-28T03:30:40Z")
I work for a major university medical center, and today a protocol was established that if a patient developed flu-like symptoms and had been to any of the areas where there are outbreaks (or had been in contact with anyone who had been to those areas) the FIRST thing to do was to put a surgical mask on the patient. So yes, while low-tech and not infallible, a mask can help prevent transmission of the virus – in both directions. ---
**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\ **Post date:** [April 28, 2009, 4:51am UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/5 "2009-04-28T04:51:53Z")
This was being discussed on NPR this afternoon. The specialist who was answering questions about Swine flu said that one of the advantages of the mask is that it keeps you from touching your mouth & nose and then getting your grubby mitts on the doorknob that everyone else uses. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 28, 2009, 11:42am UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/6 "2009-04-28T11:42:58Z")
So you have this piece of cloth over your mouth and nose, collecting flu viruses. Then what happens to them? Are they magically destroyed? Or are they transmitted to your hands every time you adjust the mask, then spread to everything you touch? I say for the average person on the street who is afraid of the flu, telling them to wear a mask is a psychological sop to reduce panic, much like the [advice in 2003](http://www.cnn.com/2003/US/02/11/emergency.supplies/)to buy duct tape and plastic sheeting to prepare for terrorist attacks. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [April 28, 2009, 1:00pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/7 "2009-04-28T13:00:50Z")
The flu is transmitted by droplets blown into the air when people talk, cough, sneeze, etc. The mask prevents these droplets from becoming airborne. Seems pretty simple and evident to me. ---
**Author:** ![muttrox](https://avatars.discourse-cdn.com/v4/letter/m/a8b319/32.png) [@muttrox](https://boards.straightdope.com/u/muttrox)\ **Post date:** [April 28, 2009, 1:27pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/8 "2009-04-28T13:27:45Z")
> [@Fear\_Itself](#): > > So you have this piece of cloth over your mouth and nose, collecting flu viruses. Then what happens to them? Are they magically destroyed? Or are they transmitted to your hands every time you adjust the mask, then spread to everything you touch? > > I say for the average person on the street who is afraid of the flu, telling them to wear a mask is a psychological sop to reduce panic, much like the [advice in 2003](http://www.cnn.com/2003/US/02/11/emergency.supplies/)to buy duct tape and plastic sheeting to prepare for terrorist attacks. Ironic username. The OP has been answered by many folks with good reasons why a surgical mask does indeed do something useful against the spread of disease. Do you have any reason to think it’s just “a psychological sop to reduce panic”? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [April 28, 2009, 3:57pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/9 "2009-04-28T15:57:26Z")
Fear Itself, if the virus is transmitted by inhaling airborne droplets or by touching something containing the virus, I would think the answer is obvious. You can’t breathe in a used mask and you wouldn’t rub it all over your face. You’d take it off, throw it in the trash and wash your hands. The viruses trapped in the mask stay trapped in the mask until they dry out and die. If you’re expecting something to be 100% perfect at preventing the disease, you’ll have to look into hazmat suits. Most of us are happy with 90%. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [April 28, 2009, 4:55pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/10 "2009-04-28T16:55:33Z")
My understanding of [surgical masks](http://www.mdp-miami.com/catalog/images/masksnmore_1986_22914359.jpg) are that they are much better at protecting the environment from the wearer rather than the other way around. So if you are sick, the mask will act as a barrier to trap your infected droplets (that sounds odd…?) but is less effective at preventing particles in the air from reaching you. Naturally, since the surgical mask is actually open, particles can still escape or enter through the open gaps. A respirator, such as [these](https://www.conney.com/wcsstore/Conney/images/fullsize/z70005.gif), however, seal around the nose and mouth and prevent particles from going in either direction, and are much better protection against whatever (germs/dust/whatever you want to protect against). The catch is getting one that fits/seals correctly, and actually wearing it properly, because if it’s not being worn properly, it isn’t much more effective than a surgical mask. This is based on information in the pharmaceutical industry, where we were fitted for masks to prevent inhalation/exposure to fine dust particles of active pharmaceutical ingredients. The key thing was particle size, and since droplets from breathing/talking/sneezing tend to be pretty big, a surgical mask can offer a level of protection that you could never get when dealing with drug powder. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 28, 2009, 6:19pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/11 "2009-04-28T18:19:39Z")
> [@dracoi](#): > > If you’re expecting something to be 100% perfect at preventing the disease, you’ll have to look into hazmat suits. Most of us are happy with 90%. I’d like to see your evidence that a surgical mask catches 90% of incoming viruses. I agree with **mnemosyne** , masks work much better trapping droplets escaping from those who are already infected than they do to protect those who are not. ---
**Author:** ![Bridget\_Burke](https://avatars.discourse-cdn.com/v4/letter/b/7cd45c/32.png) [@Bridget\_Burke](https://boards.straightdope.com/u/Bridget_Burke)\ **Post date:** [April 28, 2009, 7:46pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/12 "2009-04-28T19:46:00Z")
> [@Fear\_Itself](#): > > I’d like to see your evidence that a surgical mask catches 90% of incoming viruses. > > I agree with **mnemosyne** , masks work much better trapping droplets escaping from those who are already infected than they do to protect those who are not. I don’t know about “90%” but there was a [recent Australian study](http://www.theaustralian.news.com.au/story/0,25197,25393776-12377,00.html): > [@](#): > > Prof MacIntyre headed a study which took in more than 140 NSW children who, in 2006-07, had suffered a bout of the flu so serious they were taken to a hospital emergency room. > > Their parents were given face masks in a bid to test their effectiveness at preventing the virus’ spread. > > Parents who wore face masks during contact with their sick child were four times less likely to contract their child’s virus than those who did not. I don’t think most of us\* in the USA need masks currently, but they’re certainly a cheap & easy way to cut risks significantly. \*\* most of us:\* There are people in the USA wearing face masks right now. Like ambulatory cancer patients with dicey immune systems due to their disease or therapy. Something less exotic than swine flu could cause them severe problems. The masks definitely help. ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [April 28, 2009, 8:43pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/13 "2009-04-28T20:43:12Z")
Am I the only one who can’t breathe when they wear them things? Yeah I realize it’s probably psychological, but still… ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [April 28, 2009, 9:55pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/14 "2009-04-28T21:55:20Z")
> [@Valgard](#): > > This was being discussed on NPR this afternoon. The specialist who was answering questions about Swine flu said that one of the advantages of the mask is that it keeps you from touching your mouth & nose and then getting your grubby mitts on the doorknob that everyone else uses. INteresting. It was being discussed on NPR today (day after the above post) and \*that \*expert said that effectiveness of masks outside a clinical environment where people with the virus are “in your face” is not at all proven. ---
**Author:** ![gonzomax](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gonzomax](https://boards.straightdope.com/u/gonzomax)\ **Post date:** [April 28, 2009, 9:58pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/15 "2009-04-28T21:58:07Z")
> [@Fear\_Itself](#): > > So you have this piece of cloth over your mouth and nose, collecting flu viruses. Then what happens to them? Are they magically destroyed? Or are they transmitted to your hands every time you adjust the mask, then spread to everything you touch? > > I say for the average person on the street who is afraid of the flu, telling them to wear a mask is a psychological sop to reduce panic, much like the [advice in 2003](http://www.cnn.com/2003/US/02/11/emergency.supplies/)to buy duct tape and plastic sheeting to prepare for terrorist attacks. In this case, plastic sheet and duct tape would work very well. ---
**Author:** ![flodnak](https://avatars.discourse-cdn.com/v4/letter/f/838e76/32.png) [@flodnak](https://boards.straightdope.com/u/flodnak)\ **Post date:** [April 29, 2009, 6:21am UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/16 "2009-04-29T06:21:32Z")
These two blog posts were linked on a mailing list I read: [Masks](http://scienceblogs.com/aetiology/2006/03/masks.php) [Influenza and Masks, Redux](http://scienceblogs.com/aetiology/2007/04/influenza_and_masks_redux.php) The most recent is two years old, but neither surgical masks nor human behavior have changed all that much in the meantime. To sum up, a mask that is fitted properly and used consistently may indeed help, but without training people make many mistakes. Also, they are supposed to be disposable, and degrade with time and use. It seems that in Mexico City soldiers are just handing out masks with no information - the soldiers themselves may not have been given any training. And I know I’ve seen photos of residents wearing them in ways even I can see are wrong, like with clear gaps at the sides, or in one case a young girl wearing her mask underneath her nose :smack: I suspect they’re more for reassurance than anything else, frankly. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [April 29, 2009, 1:18pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/17 "2009-04-29T13:18:15Z")
> [@flodnak](#): > > It seems that in Mexico City soldiers are just handing out masks with no information - the soldiers themselves may not have been given any training. And I know I’ve seen photos of residents wearing them in ways even I can see are wrong, like with clear gaps at the sides, or in one case a young girl wearing her mask underneath her nose :smack: I suspect they’re more for reassurance than anything else, frankly. The Mexican news has been running regular features on how to use the masks properly for the last several days. Well, at least the Mexican news that I’m exposed to – I think it’s “Noticiero.” And of course they show street footage of all of the insanely awful ways that people are currently wearing the masks. Hope this all blows over before I have to move to Mexico City in June-July timeframe. I don’t look good in a mask. ---
**Author:** ![Swallowed\_My\_Cellphone](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@Swallowed\_My\_Cellphone](https://boards.straightdope.com/u/Swallowed_My_Cellphone)\ **Post date:** [April 29, 2009, 2:27pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/18 "2009-04-29T14:27:21Z")
> [@Fear\_Itself](#): > > I agree with **mnemosyne** , masks work much better trapping droplets escaping from those who are already infected than they do to protect those who are not. That’s how I understood they were supposed to work. Surgeons wear masks so they don’t accidentally get their evil surgeon funk germs into their sliced-open patient. Also, my cousin worked for a surgical supply place for a bit and said the masks are rated differently. So the mask I was wearing to insulate my ceiling would help keep insulation particles out of my lungs, it would do diddly to keep me from succumbing to toxic fumes or offer much protection for germs of doom. The medical mask did look a whole lot finer. It was thinner to the touch, but the “weave” looked much tighter. ETA: As for mask wearers in the news. I keep seeing this one guy front and center who only has a mask covering his mouth. HIs noes is over top. Yeah, that’ll work. ---
**Author:** ![Swallowed\_My\_Cellphone](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@Swallowed\_My\_Cellphone](https://boards.straightdope.com/u/Swallowed_My_Cellphone)\ **Post date:** [April 29, 2009, 2:37pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/19 "2009-04-29T14:37:06Z")
> [@Fear\_Itself](#): > > I’d like to see your evidence that a surgical mask catches 90% of incoming viruses. The number may be a misrepresentation of the mask rating. For example, 3M makes a HEPA-level mask for which the info says: > [@](#): > > Guard against harmful airborne bacteria and protect against viruses! > Offers HEPA-level protection against airborne allergens. Traps 99.97% of airborne particulates down to 0.3 microns! This lightweight, durable mask filters out 99.97% of airborne particles down to 0.3 microns—a level of filtration effective against almost all biological agents. Cool Flow ventilation valve makes breathing even easier. > > 3M N100 masks exceed the U.S. Centers For Disease Control (CDC) recommended rating for infection control. Some are specifically says stuff like: "Meets the CDC’s requirements for protection against tuberculosis. Compared to the one I was using during home renovations which just says: “Protects against many types of dust.” ---
**Author:** ![dotchan](https://avatars.discourse-cdn.com/v4/letter/d/9d8465/32.png) [@dotchan](https://boards.straightdope.com/u/dotchan)\ **Post date:** [April 29, 2009, 2:40pm UTC](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516/20 "2009-04-29T14:40:33Z")
> [@Swallowed\_My\_Cellphone](#): > > ETA: As for mask wearers in the news. I keep seeing this one guy front and center who only has a mask covering his mouth. HIs noes is over top. Yeah, that’ll work. _raises hand_ Guilty. Sometimes I’ll do that because mask-over-nose-and-mouth feels too suffocating, and I’m wearing the mask as to not spray spit all over the place while I’m coughing/sneezing, not to protect myself. [Next page](https://boards.straightdope.com/t/face-masks-for-flu-prevention-effective/494516.md?page=2)