# surgical masks and disease transmission **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [March 2, 2020, 11:37am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780 "2020-03-02T11:37:29Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![eschrodinger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschrodinger/32/122_2.png) [@eschrodinger](https://boards.straightdope.com/u/eschrodinger)\ **Post date:** [March 4, 2020, 8:53am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/21 "2020-03-04T08:53:22Z")
I’m not wearing a mask, and I am washing my hands more often. And it is asinine for medical professionals to tell people that masks do nothing to reduce risk for heathy wearers. Just out of curiosity, why do lay people even have access to N95 masks if we are so incompetent at wearing them? And they have long been a part of recommendations for emergency kits put out by the some of same agencies now saying they are useless because you won’t know how to wear it. If the virus is spread through particles in the air rather than droplets, then how much good is it to stand 6 feet away from a coughing person? And why bother having healthcare workers wear them if they are literally useless? I have no problem with officials telling people that they don’t really need masks, they aren’t worth the trouble of wearing and learning how to wear them properly, and you still should do all of the other Important things like hand washing, etc. But actively telling people that they won’t help is wrong, and will decrease confidence in those same officials, when people need to be able to trust them. It’s right up there with all of the assurances that it wasn’t present in the US when they weren’t even testing for it. Now we know it’s been circulating in the US for weeks. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [March 4, 2020, 9:11am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/22 "2020-03-04T09:11:40Z")
I went to a clinic for blood tests yesterday (just related to general health and heart condition), and the receptionist was not only wearing a surgical mask, but a sort of plastic shield that looked like a cross between a motorcycle helmet and an Apollo moon helmet. Before processing the form she asked questions about respiratory symptoms and other signs of coronavirus. There are a grand total of 20 cases in Ontario, FFS, in a population of 15 million, and each one of them is self-isolated at home. I had to keep asking her to repeat her questions because I couldn’t understand her through the combination of the surgical mask and the Apollo moon helmet. It’s ridiculous. The person who actually took the blood sample had no mask and no apparent paranoia about coronavirus. ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [March 4, 2020, 12:23pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/23 "2020-03-04T12:23:02Z")
> [@UDS](#): > > In other words, Brewer is _not_ affirming the view that “masks can’t possibly work because the virus can fit through the pores of the mask”. He’s saying that, if you are currently uninfected, masks will do little to stop you getting infected, but he’s affirming that they do work for minimising the spread of the infection from those who _are_ infected, which is what they are supposed to do. If you’re infected or think you could be you should wear a mask, and it will make a material. But what he’s saying isn’t true, and I suggest his reasons for saying so are the ones I outlined in my previous posts. If they didn’t help, healthcare workers wouldn’t be wearing them. Few things are foolproof, but every additional measure helps. Imagine someone attending to someone with a dry cough and a fever and the attendee decides not to don the mask they have in their house having been told they are ineffective. That doesn’t sound like proper epidemic management best practices to me. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 4, 2020, 12:35pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/24 "2020-03-04T12:35:33Z")
> [@UDS](#): > > By all means wear a surgical mask to guard against infection, if it gives you comfort. This is directly against the present advice of public health officials. Don’t wear a surgical mask simply for the sake of emotional comfort; this is a waste of a mask, and masks are currently in short supply. ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [March 4, 2020, 12:53pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/25 "2020-03-04T12:53:21Z")
> [@UDS](#): > > I think the point is that surgical masks are of more value in limiting transmission by those who are already infected than they are in guarding against infection in those who aren’t. > > By all means wear a surgical mask to guard against infection, if it gives you comfort. But understand that it offers relatively little protection, and that frequent washing of your hands with soap and hot water is likely to provide a far greater measure of protection than the mask can. There are many studies that indicate otherwise. It also makes plain old common sense. > [@](#): > > As Wang’s study revealed, rates of infection differed between doctors and nurses with respirators and those without. > > Specifically, the authors examined data collected from Jan. 2-22 at six departments within the Zhongnan Hospital. Within the 10-day period, the hospital treated 28 individuals with confirmed cases of COVID-19 and 58 “suspicious” cases. The medical staff in each department followed different safety protocols when treating the patients. > > About 280 medical staff in the hospital’s Respiratory, ICU and Infectious Diseases departments wore N95 respirators and washed their hands frequently, while about 215 in the departments of Hepatobiliary Pancreatic Surgery, Trauma and Microsurgery, and Urology wore no masks and disinfected their hands less frequently. Although the respirator group encountered confirmed cases more often than the unmasked group — more than 730% more often — no one in the respirator group became infected. > > In comparison, 10 people in the unmasked group contracted the novel disease, despite treating fewer infected patients. > > Related: 10 deadly diseases that hopped across species > > “It would appear that N95 respirators, no surprise, protect against health care acquisition of the virus,” said Dr. William Schaffner, an infectious-diseases specialist at Vanderbilt University in Tennessee, who was not involved in the current study. The small study is “reassuring in that sense,” although there was no reason to think that N95 respirators wouldn’t block out the novel coronavirus effectively, he added. > [@](#): > > Apr 3, 2012 (CIDRAP News) – A new laboratory study supports the long-debated view that airborne viruses play a role in spreading influenza and that N95 respirators provide the best protection against airborne viruses, with surgical masks affording much less. > > A US-Chinese team of researchers created a simulated examination room with mechanized mannequins spaced 6 feet apart to represent coughing and breathing humans. They found that flu viruses floated between the two and were “inhaled” by the breathing mannequin, but that an N95 respirator sealed to the mannequin’s face stopped 99.8% of them. > > A poorly fitted respirator or a loose-fitting surgical mask, by contrast, blocked only about two thirds of the virus particles. > > The researchers say their findings suggest that “anyone present in a room with a patient who has influenza might be at risk of exposure” and that properly fitted N95 respirators provide maximal protection. Their report is an early online publication in Clinical Infectious Diseases. ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [March 4, 2020, 2:55pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/26 "2020-03-04T14:55:33Z")
> [@wolfpup](#): > > I went to a clinic for blood tests yesterday (just related to general health and heart condition), and the receptionist was not only wearing a surgical mask, but a sort of plastic shield that looked like a cross between a motorcycle helmet and an Apollo moon helmet. Before processing the form she asked questions about respiratory symptoms and other signs of coronavirus. There are a grand total of 20 cases in Ontario, FFS, in a population of 15 million, and each one of them is self-isolated at home. I had to keep asking her to repeat her questions because I couldn’t understand her through the combination of the surgical mask and the Apollo moon helmet. It’s ridiculous. The person who actually took the blood sample had no mask and no apparent paranoia about coronavirus. Perhaps the receptionist is immunosuppressed. When I was in chemo, I was told by actual real doctors to wear a mask for my protection when I was in public. ---
**Author:** ![eschrodinger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschrodinger/32/122_2.png) [@eschrodinger](https://boards.straightdope.com/u/eschrodinger)\ **Post date:** [March 4, 2020, 6:57pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/27 "2020-03-04T18:57:15Z")
Also, it may be true that the 20 known cases are the “grand total,” but unless there has been true surveillance testing it is really unknown how many cases there are. In the US, the CDC would not test unless the suspected case had a known exposure. Do you know what the testing criteria are there? In Hawaii at one point, a state that normally has 700 flights a month from Japan and South Korea, where the coronavirus was circulating in the community, doctors requested testing of 9 patients based on clinical diagnostic procedures. The samples they sent for testing not only were not tested because they did not meet the criteria of travel to an infected area or known contact with a known case, but the samples were also destroyed. In the US at least, no one has any business referring to the known cases as the grand total. I know more testing has been done in Canada than here, but it didn’t sound like there has been the kind of testing that would ensure definitively a known number of cases. ---
**Author:** ![Saturn\_Dreams](https://avatars.discourse-cdn.com/v4/letter/s/dc4da7/32.png) [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)\ **Post date:** [March 4, 2020, 10:49pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/28 "2020-03-04T22:49:33Z")
> [@KidCharlemagne](#): > > There are many studies that indicate otherwise. It also makes plain old common sense. That study you quoted is about respirators, not surgical masks. Those are two different things. ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [March 4, 2020, 11:03pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/29 "2020-03-04T23:03:02Z")
> [@Saturn\_Dreams](#): > > That study you quoted is about respirators, not surgical masks. Those are two different things. We’ve been discussing N95s throughout this thread, yourself included. I think the OP used masks as a metanym for both masks and respirators. The vast majority of the public conversation is around the N95s. Nevertheless, the study says surgical masks are also effective but less so. ---
**Author:** ![Saturn\_Dreams](https://avatars.discourse-cdn.com/v4/letter/s/dc4da7/32.png) [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)\ **Post date:** [March 4, 2020, 11:50pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/30 "2020-03-04T23:50:21Z")
> [@KidCharlemagne](#): > > We’ve been discussing N95s throughout this thread, yourself included. I think the OP used masks as a metanym for both masks and respirators. The vast majority of the public conversation is around the N95s. I beg to differ. Double check the op. ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [March 5, 2020, 12:28am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/31 "2020-03-05T00:28:59Z")
> [@Saturn\_Dreams](#): > > I beg to differ. Double check the op. Whatever. The second study covered surgical masks anyway. All my points still hold. ---
**Author:** ![Saturn\_Dreams](https://avatars.discourse-cdn.com/v4/letter/s/dc4da7/32.png) [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)\ **Post date:** [March 5, 2020, 2:30am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/32 "2020-03-05T02:30:02Z")
> [@KidCharlemagne](#): > > Whatever. The second study covered surgical masks anyway. All my points still hold. And what point is that exactly? If you’re saying wearing masks will block some droplets of virus laden saliva reaching your nose and mouth areas, I agree. If that’s the protection you’re looking for, turning your back to them would work much better. If you’re saying masks help prevent the wearer from getting infected, I disagree. There is no doctor, scientist or study that recommends wearing a surgical mask as a way of preventing anything other than an already infected patient from spreading germs through coughing and sneezing. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [March 5, 2020, 10:24am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/33 "2020-03-05T10:24:09Z")
> [@Saturn\_Dreams](#): > > If you’re saying wearing masks will block some droplets of virus laden saliva reaching your nose and mouth areas, I agree. If that’s the protection you’re looking for, turning your back to them would work much better. I think that’s being a bit silly; this is akin to saying staying at home is better cranial protection than riding a bike wearing a helmet. If a person needs to go out and speak to people, wearing a surgical mask is better than nothing. It may not be as good as N95 which may not be as good as a respirator but “not as good as” and “useless” are not synonyms. ---
**Author:** ![Saturn\_Dreams](https://avatars.discourse-cdn.com/v4/letter/s/dc4da7/32.png) [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)\ **Post date:** [March 5, 2020, 12:12pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/34 "2020-03-05T12:12:19Z")
> [@Mijin](#): > > I think that’s being a bit silly; this is akin to saying staying at home is better cranial protection than riding a bike wearing a helmet. If a person needs to go out and speak to people, wearing a surgical mask is better than nothing. It may not be as good as N95 which may not be as good as a respirator but “not as good as” and “useless” are not synonyms. Who said surgical masks were useless? I questioned to what purpose people are wearing them. Some usages are not as effective as others. “Not as effective” and “useless” are not synonyms. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 5, 2020, 12:45pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/35 "2020-03-05T12:45:46Z")
> [@UDS](#): > > You’d rather have the mask on, obvously. But someone sneezing directly into your face is probably not the transmission risk you most need to worry about. Speak for yourself. I take public transit every day. Are there other forms of transmission I am subject to? Of course. But “stranger sneezing close to my face” is not all that rare an event during cold season. Also, the comment above about masks not being useful because they get damp so you need to replace them strikes me as odd. I bought a lot of surgical masks at the start of the SARS scare, thinking they might become scarce if it broke out. I had them in my closet for years, then one day had to fly when I had a cold, so I wore one, thinking it would be polite not to spread my cold. That was the most comfortable flight I’d had in years, and I realized that a lot of what I thought was “jet lag” was actually dehydration, from breathing the dry eir in airplanes. I now wear a mask every time I have a long flight because the extra moisture it holds makes me a lot more comfortable. I don’t have a cite handy, but I’ve recently seen a bunch of data about how people are more susceptible to many diseases when their mucus membranes dry out, and that low humidity increases the risk of catching colds and flu. I suspect that JUST THE ADDED MOISTURE in your nose from wearing a surgical mask may provide a little protection. I’m not yet wearing those masks on my commute, but I may next week. Or maybe I’ll work from home. ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [March 5, 2020, 1:32pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/36 "2020-03-05T13:32:29Z")
> [@Saturn\_Dreams](#): > > And what point is that exactly? If you’re saying wearing masks will block some droplets of virus laden saliva reaching your nose and mouth areas, I agree. If that’s the protection you’re looking for, turning your back to them would work much better. > > If you’re saying masks help prevent the wearer from getting infected, I disagree. There is no doctor, scientist or study that recommends wearing a surgical mask as a way of preventing anything other than an already infected patient from spreading germs through coughing and sneezing. I only hope you are as immune to SARS-Cov2 as you are to reason. Since you seem dead set on being contrary and not following data or arguments, this is my last attempt. I’ve already explained why doctors are not recommending them. To repeat: 1. Fear a shortage of masks for those who urgently need them 2. Fear a panic from those who don’t get them 3. Fear the mask will provide a false sense of security leading to the abandonment of other preventative measures. The general public also needs to be informed how to don, wear, remove, and dispose them And it being better if you turn your back vs wearing a mask is one of the dumber arguments I’ve since in GD let alone GQ. Anyway if common sense doesn’t convince you: > **[Effectiveness of facemasks to reduce exposure hazards for airborne infections...](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306645/#!po=7.89474)** > > Facemasks are widely used as a protective measure by general public to prevent inhalation of airborne pathogens including seasonal, swine and other forms of influenza and severe acute respiratory syndrome (SARS), etc. However, scientific data on... > [@](#): > > The level of protection was parametrized by reduction of exposure. It was observed that under pseudo-steady conditions, the PD is 45 per cent for normal wearing scenarios. Under transient scenarios, the PD varied from 33 to 100 per cent with different parameters. > **[Face Mask Use and Control of Respiratory Virus Transmission in Households](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2662657/?report=reader)** > > Mask use is associated with low adherence, but adherent mask users are significantly protected against seasonal disease.Many countries are stockpiling face masks for use as a nonpharmaceutical intervention to control virus transmission during an... > [@](#): > > We estimated that, irrespective of the assumed value for the incubation period (1 or 2 days), the relative reduction in the daily risk of acquiring a respiratory infection associated with adherent mask use (P2 or surgical) was in the range of 60%–80%. > **[Professional and home-made face masks reduce exposure to respiratory...](https://pubmed.ncbi.nlm.nih.gov/18612429/)** > > Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as... > [@](#): > > CONCLUSIONS/SIGNIFICANCE: > Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [March 5, 2020, 5:09pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/37 "2020-03-05T17:09:24Z")
> [@Saturn\_Dreams](#): > > Who said surgical masks were useless? I questioned to what purpose people are wearing them. Some usages are not as effective as others. “Not as effective” and “useless” are not synonyms. The idea that surgical masks are useless for self-protection is implied by your responses where you’ve handwaved any suggestion of their utility, culminating in the facetious response that “turning your back […] would work much better”. If you’re now agreeing that they offer some protection, to the wearer, but are far from optimal, and there are wearables that provide significantly more protection…then we’re in agreement. I’ve said exactly this upthread, and in fact we can completely ignore the position of surgical masks being optimal / offering full protection, as nobody has claimed that. Nobody _is_ going to claim that. Surgical masks offer some basic protection from a direct spray of particles and from touching the nose or mouth. The fact that we can find things that offer additional protection does not invalidate this. ---
**Author:** ![Corry\_El](https://avatars.discourse-cdn.com/v4/letter/c/ecae2f/32.png) [@Corry\_El](https://boards.straightdope.com/u/Corry_El)\ **Post date:** [March 5, 2020, 5:34pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/38 "2020-03-05T17:34:42Z")
> [@nelliebly](#): > > Quote: > Brewer says masks are used to keep someone who is infected from spreading it to others. If you’re not sick, you don’t need to wear one, and if you do, it’s not preventing you from getting sick. Common surgical masks block the droplets coming out of a sick person from getting into the air, but they are not tight enough to prevent what’s already in the air from getting in. > > I’m kind of thinking with those credentials, he’s not too likely to say asinine things about an epidemic virus. This was sort of covered, but more specifically he’s definitely talking about ‘mask not tight enough’, not that the virus (or droplets containing it) would go through. Assume we’re talking about N95 masks. Assume (might or might not be realistic) it’s tight or well fitted enough. I believe in fact trying to condition public sentiment and keep people calm (nowhere remotely near enough N95’s around) is a factor in certain statements. Maybe not the one quoted but in media presentation of expert opinion on the whole. ‘N95’s are useless so please, don’t buy them all up’ has a sort of contradiction to it. But aside from attempted panic control it’s pretty irrelevant at this point to tell people not to buy them. They’re gone from stores, prices on Ebay etc are sky high. If some people calm down and the bids go down a little, other people will just be more incentivized to scoop them up at slightly less ridiculous prices. If a significant supply of N95’s is really still in the private system and it would really help the public health effort to get hold of those for medical personnel, the govt needs to find a way to do that. But I doubt the remaining private supply for sale now is significant. But ‘won’t help’? I doubt that. A panacea obviously not, putting it down, shifting it around and therefore touching your face with unwashed hands, not well enough fitting in the first place…all valid points about how the usefulness could be limited. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [March 5, 2020, 8:23pm UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/39 "2020-03-05T20:23:16Z")
> [@Saturn\_Dreams](#): > > Who said surgical masks were useless? Probably a good idea to read the thread before asking questions like that: > [@Broomstick](#): > > Touching/fiddling/pulling them down are all mistakes the untrained commonly make and which sort of make wearing masks pointless. No offense intended: I read these threads because I don’t know the information. ---
**Author:** ![Saturn\_Dreams](https://avatars.discourse-cdn.com/v4/letter/s/dc4da7/32.png) [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)\ **Post date:** [March 6, 2020, 12:33am UTC](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780/40 "2020-03-06T00:33:04Z")
> [@KidCharlemagne](#): > > I only hope you are as immune to SARS-Cov2 as you are to reason. Since you seem dead set on being contrary and not following data or arguments, this is my last attempt. I’ve already explained why doctors are not recommending them. To repeat: > > 1. Fear a shortage of masks for those who urgently need them > 2. Fear a panic from those who don’t get them > 3. Fear the mask will provide a false sense of security leading to the abandonment of other preventative measures. The general public also needs to be informed how to don, wear, remove, and dispose them > > And it being better if you turn your back vs wearing a mask is one of the dumber arguments I’ve since in GD let alone GQ. I agree with these points (on why doctor’s discourage the general public from using face masks). If they had any significant efficiency do you think doctors and scientists would discourage their usage by the general public? None of your points are relevant to the effectiveness of face masks. And what’s so dumb about turning your back towards someone who is spewing saliva at you? That is much better protection than facing them with a mask. Staying away six feet away from them as the CDC suggest is a good idea too. I read your cites. So they found masks offered some level of “protection” in a controlled environment. I get that. But you realize that’s like saying using a newspaper to cover your head from the rain will “protect” you from getting wet? Sure, it will block some rain drops from hitting your head but its effectiveness won’t last long and you’re still going to get wet. There are much better ways of staying dry, including staying indoors. Here are some cites from me. > **[Face masks to prevent transmission of influenza virus: a systematic review |...](https://www.cambridge.org/core/journals/epidemiology-and-infection/article/face-masks-to-prevent-transmission-of-influenza-virus-a-systematic-review/64D368496EBDE0AFCC6639CCC9D8BC05)** > > Face masks to prevent transmission of influenza virus: a systematic review - Volume 138 Issue 4 > [@](#): > > In conclusion there remains a substantial gap in the scientific literature on the effectiveness of face masks to reduce transmission of influenza virus infection. While there is some experimental evidence that masks should be able to reduce infectiousness under controlled conditions [7], there is less evidence on whether this translates to effectiveness in natural settings. There is little evidence to support the effectiveness of face masks to reduce the risk of infection. > **[Update: Why Face Masks Don’t Work: A Revealing Review - Oral Health Group](https://www.oralhealthgroup.com/features/face-masks-dont-work-revealing-review/)** > > For at least three decades face masks has been deemed an essential component of the personal protective equipment worn by dental personnel. > [@](#): > > In their well-referenced 2011 article on respiratory protection for healthcare workers, Drs. Harriman and Brosseau conclude that, “facemasks will not protect against the inhalation of aerosols.” 11 Following their 2015 literature review, Dr. Zhou and colleagues stated, “There is a lack of substantiated evidence to support claims that facemasks protect either patient or surgeon from infectious contamination.” 25 In the same year Dr. R. MacIntyre noted that randomized controlled trials of facemasks failed to prove their efficacy. > [@](#): > > In 2015, Dr. Leonie Walker, Principal Researcher of the New Zealand Nurses Organization succinctly described- within a historical context – the inadequacies of facemasks, “Health care workers have long relied heavily on surgical masks to provide protection against influenza and other infections. Yet there are no convincing scientific data that support the effectiveness of masks for respiratory protection. The masks we use are not designed for such purposes, and when tested, they have proved to vary widely in filtration capability, allowing penetration of aerosol particles ranging from four to 90%.” 35 [Previous page](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780.md?page=1) [Next page](https://boards.straightdope.com/t/surgical-masks-and-disease-transmission/848780.md?page=3)