# Why was the American public told not to wear face masks? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [March 31, 2020, 3:06pm UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742 "2020-03-31T15:06:32Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 2, 2020, 11:09pm UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/101 "2020-04-02T23:09:08Z")
> [@SlackerInc](#): > > No, I haven’t “got that” because you are wrong. _According to Dr. Vanessa Raabe, assistant professor of pediatric infectious diseases at NYU Langone, there’s little scientific evidence to show that medical face masks or other forms of facial protective gear alone are effective in keeping healthy individuals from inhaling infectious particles._ ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 2, 2020, 11:10pm UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/102 "2020-04-02T23:10:26Z")
> [@SlackerInc](#): > > No, I haven’t “got that” because you are wrong. _According to Dr. Vanessa Raabe, assistant professor of pediatric infectious diseases at NYU Langone, there’s little scientific evidence to show that medical face masks or other forms of facial protective gear alone are effective in keeping healthy individuals from inhaling infectious particles._ And this is why we cant have nice things. You still think the mask will protect you. ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [April 2, 2020, 11:55pm UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/103 "2020-04-02T23:55:38Z")
You do know what the word “alone” means? 😕 ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [April 3, 2020, 12:08am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/104 "2020-04-03T00:08:01Z")
I am working on masks for Mr VOW and The Daughter to wear tomorrow, to Mr VOW’s echocardiogram appointment. ~VOW ---
**Author:** ![elbows](https://avatars.discourse-cdn.com/v4/letter/e/b3f665/32.png) [@elbows](https://boards.straightdope.com/u/elbows)\ **Post date:** [April 3, 2020, 12:15am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/105 "2020-04-03T00:15:23Z")
The masks don’t keep you from getting infected. In a culture where most people wear masks there is far less spread. Not because the mask protects you from getting it, but because it greatly decreases the spread by those contagious but not yet having symptoms, because THEY ARE wearing a mask. Seriously, how can you still not get this? Everyone in America right now, who IS contagious and have no idea, because they haven’t yet developed symptoms, is spreading for up to seven days. Everywhere they go. If they were wearing a mask they would contaminate far fewer people and places. It’s that simple. If everybody wore masks spread would be greatly reduced. Your chance of catching it would then also be reduced. ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [April 3, 2020, 12:49am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/106 "2020-04-03T00:49:08Z")
The tides are changing. The mayor of the City of Los Angeles, and the Director of the LA County Department of Public Health are both strongly recommending that people wear masks when out in public. Specifically, any mask BUT the N95 masks which should be reserved for health care workers. Gil Garcetti has modeled a homemade mask, and said makeshift masks or even bandanas could be worn. ~VOW ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [April 3, 2020, 12:57am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/107 "2020-04-03T00:57:09Z")
> [@elbows](#): > > Seriously, how can you still not get this? Everyone in America right now, who IS contagious and have no idea, because they haven’t yet developed symptoms, is spreading for up to seven days. Well, to be fair, we’ve only just known that for the past 24 hours. [If we’re the governor of Georgia, that is.](https://www.nbcnews.com/politics/politics-news/georgia-gov-brian-kemp-admits-he-just-learned-asymptomatic-people-n1174976) > [@Brian Kemp](#): > > So what we’ve been telling people from directives from the CDC for weeks now, that if you start feeling bad stay home, those individuals could have been infecting people before they ever felt bad. > > Well we didn’t know that until the last 24 hours. This is a game-changer for us. ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [April 3, 2020, 1:10am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/108 "2020-04-03T01:10:12Z")
> **[The evidence for everyone wearing masks, explained](https://www.vox.com/2020/3/31/21198132/coronavirus-covid-face-masks-n95-respirator-ppe-shortage)** > > There is some evidence that the public should wear masks. But let doctors and nurses get them first. > [@](#): > > Based on the evidence, masks appear to help both the wearer and other people. The latter is particularly important for the coronavirus, since the disease can spread from those with few to no symptoms. So whether it’s for selfish or altruistic reasons, there could be a benefit to everyone, even the asymptomatic, wearing masks — as is standard and recommended by public officials in many Asian countries (including Taiwan and South Korea, both of which have done a better job containing Covid-19 than the US).[…] > > Regardless of what the CDC decides, its messaging has backfired: As health care workers have clamored for masks, it’s become harder to tell the public that masks wouldn’t benefit everyone else. By obfuscating and failing to fully explain the issue, experts told me, officials have likely sown distrust toward their guidance — and the public has rushed to buy masks anyway. > > I can’t explain the motives behind the CDC’s stance. But based on my conversations with other experts and officials, it seems many people are afraid of saying anything that could exacerbate the PPE shortage for health care workers or get members of the general public to think — incorrectly — that they could ease on social distancing if they just wear a mask. I’m not sure if the people here have been convinced by the propaganda, or if they are disingenuously trying to participate in perpetuating it. If it’s the latter, stop it. This board of all places is not the place for that. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 3, 2020, 1:41am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/109 "2020-04-03T01:41:33Z")
> [@SlackerInc](#): > > [The coronavirus mask debate, explained - Vox](https://www.vox.com/2020/3/31/21198132/coronavirus-covid-face-masks-n95-respirator-ppe-shortage) > > I’m not sure if the people here have been convinced by the propaganda, or if they are disingenuously trying to participate in perpetuating it. If it’s the latter, stop it. This board of all places is not the place for that. I am not sure what you are getting from that article\*\*- which wasnt written by a medical professional. \*\* _"But the best protection masks offer may be protection from the wearer. While the evidence is thin on how much masks protect the wearer from coronavirus — since it’s unclear if the virus spreads much through airborne droplets — it’s true that the masks stop people from spreading their own droplets: When you breathe, talk, laugh, sigh, yawn, sneeze, or cough in public, you’re less likely to get droplets on a checkout machine, dining table, or anywhere else if you have a mask on. That could stop people, even those who are asymptomatic, from spreading infection…The quality of the research on this topic is weak, with a lot of small, underpowered studies. “There’s not this overwhelming body of evidence that says that’s exactly what we should be doing right now,” Saskia Popescu, an epidemiologist focused on hospital preparedness, told me. “That’s why there hasn’t been an earlier push from public health agencies.”…A big issue was adherence; people were often bad at actually wearing masks, which, unsurprisingly, diminished their effectiveness. …There are some risks. If people start feeling like masks make them invulnerable and begin acting recklessly — ignoring social distancing or failing to wash their hands — that could actually make wearing masks worse than not wearing them…There’s also a risk of improper use actually exposing people to more illness. If people don’t put on the masks correctly, they won’t be as protective (though some barrier is likely better than none). If people touch the front of their masks and then touch other parts of their face, they can infect themselves with droplets their mask caught. If people reuse masks, they can breathe in virus-containing droplets from the masks while putting them on or taking them off._ Medical professional arent wearing the masks to protect\* them from you\*, they are wearing the masks to protect\* you from them.\* This isnt some secret conspiracy. Masks dont protect the wearer, they protect others from the wearer- IF the mask is used correctly- which they aren’t. There’s no “propaganda”, no secret conspiracy. And like the article says “_If people start feeling like masks make them invulnerable and begin acting recklessly — ignoring social distancing or failing to wash their hands — that could actually make wearing masks worse than not wearing them._” So- **stay the fuck home.** \*Dont go out in public wearing a mask that you don’t know how to use (and you don’t), thinking that you are now protected. \* Now sure- if you have to go out in public as you ran out of food at home, then why not wear a home made cloth mask to protect others from you, just in case you are infected but have no symptoms. But you are not protecting yourself. You are maybe protecting others. ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [April 3, 2020, 2:24am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/110 "2020-04-03T02:24:17Z")
This whole business of the public wearing any type of mask may make them more reckless…is reading like bullshit to me. People NOT wearing masks are already behaving like idiots. I don’t see how wearing masks will make everyone behave like an idiot. Instead, people making the effort of wearing some type of protection are behaving more responsibly. The idiots are licking the products on the shelves in WalMart and laughing, "What coronavirus? " Masks offer SOME protection. Otherwise, in hospitals where the N95 masks have run out, why are the personnel covering up with anything from diapers to bandanas? Can you imagine telling hospital personnel, “After your last N95 mask falls apart, don’t bother with substituting anything. Just go forth bare faced and do your job.” SOMEthing is better than NOTHING. ~VOW ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [April 3, 2020, 2:34am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/111 "2020-04-03T02:34:29Z")
> [@DrDeth](#): > > Now sure- if you have to go out in public as you ran out of food at home, then why not wear a home made cloth mask to protect others from you, just in case you are infected but have no symptoms. But you are not protecting yourself. You are maybe protecting others. The truth is that you are perpetuating misinformation, whether knowingly or unknowingly. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [April 3, 2020, 4:44am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/112 "2020-04-03T04:44:54Z")
> [@DrDeth](#): > > For the fourth time now- wearing a mask doesnt make _you_ any safer. It makes those around you safer if you have the disease. The fact that you cant understand this is exactly why the medical experts are saying don’t mask. > > If\*\* YOU \*\*wear a mask you are not making the trip any safer for **YOU** , just for others around you if you are sick. Got that? > > So that "scary trip " is just as risky unless\* everyone \*wears masks. And how do you respond to the [peer reviewed articles](https://boards.straightdope.com/sdmb/showpost.php?p=22223539&postcount=69) I included in my previous post that show surgical masks clearly make people safer against a whole range of infectious diseases? ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 3, 2020, 4:56am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/113 "2020-04-03T04:56:54Z")
> [@SlackerInc](#): > > The truth is that you are perpetuating misinformation, whether knowingly or unknowingly. No, I am quoting medical experts. \*You \*are the one spreading misinformation. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 3, 2020, 5:10am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/114 "2020-04-03T05:10:17Z")
> [@Shalmanese](#): > > And how do you respond to the [peer reviewed articles](https://boards.straightdope.com/sdmb/showpost.php?p=22223539&postcount=69) I included in my previous post that show surgical masks clearly make people safer against a whole range of infectious diseases? Let’s take that first one "_The highest quality cluster‐RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Benefit from reduced transmission from children to household members is broadly supported also in other study designs where the potential for confounding is greater. Nine case‐control studies suggested implementing transmission barriers, isolation and hygienic measures are effective at containing respiratory virus epidemics. Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. N95 respirators were non‐inferior to simple surgical masks but more expensive, uncomfortable and irritating to skin…Physical means might prevent the spread of virus by aerosols or large droplets from infected to susceptible people (such as by using masks and distancing measures) "_ So- wash your fucking hands. And if you are sick, masks can keep you from spreading it to others. See, you dont know how to read studies. You quoted _"Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. "_ But you didnt read or quote that fact that they were talking about the masks being worn on the INFECTED people, which protects the susceptible. In other words, as I have said over and over and over- a mask does not protect YOU, it protects other people _from_ you. So, unless you are sick, a mask doesnt help. Now, with covid , quite a few people are asymptomatic, so yes, if\* they\* wore a mask, it would help, which is what they are saying. And what I have been saying. **Wearing a mask does not protect you from covid.** Washing your hands and staying home does. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 3, 2020, 5:19am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/115 "2020-04-03T05:19:53Z")
> [@VOW](#): > > … > > Masks offer SOME protection. Otherwise, in hospitals where the N95 masks have run out, why are the personnel covering up with anything from diapers to bandanas? > … Masks offer quite a bit of protection- if you are sick and if you know how to wear them right. The hospital workers are not wearing masks to protect them from the sick people, but to protect the patients. Just like when a surgeon washes his hands for like ten minutes then dons gloves- it aint to protect his hands from your germs, it’s to protect your insides from HIS germs. Hospital workers work on the assumption that they may well have some nasty infection disease as they are constantly exposed. They wear those masks to protect you, not them. And they wear them properly- which you wont do. In fact, no lay person will. You fiddle with them, scratch, ect, or as seen in Italy- remove them to smoke. :rolleyes::eek: So sure, since we could be asymptomatic, it cant hurt for you to make a cheap cloth mask and wear it when you go out- to protect others. It wont do shit to protect you. But go out as little as fucking possible. \*\*Wash your hands, stay home. \*\* ---
**Author:** ![SuperAbe](https://avatars.discourse-cdn.com/v4/letter/s/f17d59/32.png) [@SuperAbe](https://boards.straightdope.com/u/SuperAbe)\ **Post date:** [April 3, 2020, 6:15am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/116 "2020-04-03T06:15:59Z")
First, just read everything **DrDeth** has been writing: that’s the consensus expert opinion. Second, if you want a well-referenced summary of the field, read [this summary](http://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data) from an emeritus pulmonologist on what masks are for (protecting others from symptomatic respiratory patients), why most folks can’t use them correctly (I see trained physicians screw this up sometimes), and why DIY masks aren’t going to help much if at all (filtration is complicated). Third, there isn’t some mass conspiracy to keep people in the U.S. from using them: most ID and Epi docs have long found the routine use in East Asian populations to be confusing. And - as has already been mentioned - the relationship between which countries populations use masks and which do not doesn’t seem to have any meaningful relationship with _any_ respiratory disease suppression - current or otherwise. This is true even when you model N95/P100 masks that are more effective but much harder to use correctly (mostly because they’re really uncomfortable to wear for more than a few minutes - even with professional fitting and training). Fourth, “But wearing masks can’t hurt, can it? I mean they stop something?” Without getting into the weeds, here, let me put it this way: masks on people who (mostly) use them incorrectly in public are simply the least important factor. Reducing social interactions? Better. Increasing physical distance? Better. Staying home? Awesome. Will masks help protect against people actively coughing up a lung? Sure. You know what works better than that? Having the idiot with a coughing fit wash their hands and STAY HOME. Finally, I am well away of the rumors that the CDC may be about to change its recommendations and that a number of cities have started to issue orders to wear them. I have not been able to find a single scientific article that suggests there is any evidence that this will be useful. You know what is helpful? STAYING HOME. Stay safe, folks. We’ll be at this for a while yet. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 3, 2020, 6:21am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/117 "2020-04-03T06:21:40Z")
> [@SuperAbe](#): > > First, just read everything **DrDeth** has been writing: that’s the consensus expert opinion. > > Second, if you want a well-referenced summary of the field, read [this summary](http://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data) from an emeritus pulmonologist on what masks are for (protecting others from symptomatic respiratory patients), why most folks can’t use them correctly (I see trained physicians screw this up sometimes), and why DIY masks aren’t going to help much if at all (filtration is complicated)… Thanks Abe. and excellent cite! ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [April 3, 2020, 7:29am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/118 "2020-04-03T07:29:05Z")
:rolleyes: These experts you keep referring to have not said that the N95 masks (which, again, is what I have) are needed by healthcare workers solely to protect other patients (which doesn’t make a lot of sense for those who work with Covid-19 patients all day long). And the many healthcare workers interviewed by the NY Times and others who express fear because of a concern about shortage of PPV are not expressing fear that they will infect someone else, but that they and their families will get infected. If your narrative were right, then all the people working with Covid patients would be getting infected, and it would be crazy for any of them to go home to their families. They should all be sleeping at the hospital! Think about what you are saying. Anyway, on to a little more plausible corner of our reality, an interesting article: > **[Testing Shows Type of Cloth Used in Homemade Masks Makes a Difference,...](https://newsroom.wakehealth.edu/news-releases/2020/04/testing-shows-type-of-cloth-used-in-homemade-masks-makes-a-difference?fbclid=IwAR0rleQBATohnHRMaGLoHNkBAK4wt0l53rzD53TY6uQRAJOJ1uBy28wxIrU)** > > Homemade masks can play an important role in the fight against the COVID-19 pandemic but the type of fabric used is key to their effectiveness, according to tests performed at Wake Forest Baptist Health. > [@](#): > > In an effort to determine the protective qualities of homemade cloth masks, a team of doctors and scientists used rigorous testing, known as particulate filtration, to evaluate 13 different designs from approximately 400 masks made by community volunteers. > The goal was to find out which type of mask best removed particles 0.3 – 1.0 microns in diameter, the size of many viruses and bacteria, in comparison to standard surgical masks and N95 respirators.[…] > > What the test team found was that the masks’ effectiveness varied widely. The best homemade masks achieved 79% filtration as compared to surgical masks (62% to 65%) and N95 masks (97%). But other homemade masks tested performed significantly worse, sometimes demonstrating as little as 1% filtration, Segal said. ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [April 3, 2020, 7:52am UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/119 "2020-04-03T07:52:54Z")
This one is interesting. It is probably even more thumbs down overall on masks for civilians than \*\*DD \*\*is, but a big part of that is their evaluation that both cloth masks and N95 respirators are ineffectual for “source control” (which is what DD is, laughably, claiming their sole purpose is, even in healthcare settings). They also believe cloth and surgical masks are ineffectual in protecting healthy medical personnel, but properly fitted N95 respirators (again, which is what I have) \*are \*in fact effective at protecting the healthy. > **[COMMENTARY: Masks-for-all for COVID-19 not based on sound data](https://www.cidrap.umn.edu/covid-19/commentary-masks-all-covid-19-not-based-sound-data)** > [@](#): > > Following a recommendation that cloth masks be explored for use in healthcare settings during the next influenza pandemic,3 The National Institute for Occupational Safety and Health (NIOSH) conducted a study of the filter performance on clothing materials and articles, including commercial cloth masks marketed for air pollution and allergens, sweatshirts, t-shirts, and scarfs.4 > > Filter efficiency was measured across a wide range of small particle sizes (0.02 to 1 µm) at 33 and 99 L/min. N95 respirators had efficiencies greater than 95% (as expected). For the entire range of particles tested, t-shirts had 10% efficiency, scarves 10% to 20%, cloth masks 10% to 30%, sweatshirts 20% to 40%, and towels 40%. All of the cloth masks and materials had near zero efficiency at 0.3 µm, a particle size that easily penetrates into the lungs.4 > > Another study evaluated 44 masks, respirators, and other materials with similar methods and small aerosols (0.08 and 0.22 µm).5 N95 FFR filter efficiency was greater than 95%. Medical masks exhibited 55% efficiency, general masks 38% and handkerchiefs 2% (one layer) to 13% (four layers).[…] > > A recent pooled analysis of two earlier trials comparing medical masks and N95 filtering facepiece respirators with controls (no protection) found that healthcare workers continuously wearing N95 FFRs were 54% less likely to experience respiratory viral infections than controls (P = 0.03), while those wearing medical masks were only 12% less likely than controls (P = 0.48; result is not significantly different from zero).51[…] > > In sum, this study, the meta-analyses, randomized controlled trial described above,49,51 and laboratory data showing high filter efficiency and high achievable fit factors lead us to conclude that N95 FFRs offer superior protection from inhalable infectious aerosols likely to be encountered when caring for suspected or confirmed COVID-19 patients.[…] > > Cloth masks are ineffective as source control and PPE, surgical masks have some role to play in preventing emissions from infected patients, and respirators are the best choice for protecting healthcare and other frontline workers, but not recommended for source control. These recommendations apply to pandemic and non-pandemic situations. ---
**Author:** ![Wrenching\_Spanners](https://avatars.discourse-cdn.com/v4/letter/w/ecb155/32.png) [@Wrenching\_Spanners](https://boards.straightdope.com/u/Wrenching_Spanners)\ **Post date:** [April 3, 2020, 12:03pm UTC](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742/120 "2020-04-03T12:03:31Z")
US set to recommend wearing of masks. [Coronavirus: New York forced to redistribute ventilators - BBC News](https://www.bbc.co.uk/news/world-us-canada-52148534) Dr Deborah Birx, one of President Trump’s coronavirus advisers, expressed caution about general mask-wearing. “We don’t want people to get an artificial sense of protection,” she said. “They’re an additive.” I think once standard surgical masks (example: [https://www.medisave.co.uk/surgeons-face-mask-with-loops-per-50.html](https://www.medisave.co.uk/surgeons-face-mask-with-loops-per-50.html)) are widely available for retail purchase, the recommendation will be to wear them. It’s simply a numbers game. Even if a mask is only 55% effective, that’s a big deal in terms of exponential progression. Cut that rate in half for improper mask use, and it’s still a difference maker. It’s the combination of factors including isolation, social distancing, good hygiene and surgical masks that’s going to make the difference. But suppose that the combination of isolation, social distancing, and good hygiene are 90% effective. Raising that rate of effectiveness to 95.5% or even 92.75% is going to make a long term difference in slowing the rate of infection and keeping the number of hospital cases manageable. I also think masks are going to become mandatory for people who are interacting with the general public such as supermarket cashiers. I haven’t seen the science that determined why six feet is the recommended social distance, but I assume the biggest factor is breath dispersal. The area of breath dispersal’s going to be much smaller for someone wearing a mask. [Previous page](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742.md?page=5) [Next page](https://boards.straightdope.com/t/why-was-the-american-public-told-not-to-wear-face-masks/850742.md?page=7)