Respiratory virus shedding in exhaled breath and efficacy of face masks
nature.com
nature.com
https://www.ncbi.nlm.nih.gov/pubmed/32226116
And there's at least one study that found healthcare workers are at higher risk of infection during medical procedures that create aerosols.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338532/
Perhaps it's some human bias and we dread the idea that simply sharing the same atmosphere puts us at risk?
This could be something very positive actually, and lead to rapid non-invasive testing. Imagine virus testing as part of the air filters on planes and cruise ships, could be a very powerful tool for preventing outbreaks.
https://www.statnews.com/2020/03/16/coronavirus-can-become-a...
> The reason the measles is so, well, viral, is that the microbe is so small and hardy that it is able to stay suspended in the air where an infected person coughed or sneezed for up to two hours, making it one of the only viruses that can exist as a true aerosol.
> Now there are conflicting reports on whether the new coronavirus can. The studies suggesting that it can be aerosolized are only preliminary, and other research contradicts it, finding no aerosolized coronavirus particles in the hospital rooms of Covid-19 patients.
We don't know that coughing alone generates significant amounts of coronavirus aerosols. The studies I've seen so far indicate it's not a major source of transmission; that droplets are the concern.
That thing just spreads like wildfire.
I don't care if the experts don't want a run on masks. Anyone of modest intelligence knows that paper with little holes in it impedes the movement of air and droplets. Even if a mask is poorly sealed, surely it does something for both the infected and the uninfected, yet we've allowed the authorities, the experts, to gaslight us into accepting that the sky is blue so that they could augment their supply with masks intended to be sold to civilians. Under normal circumstances, individuals can afford to wait for evidence and listen to it. Now there are people who are going to die because they trusted the idea that they shouldn't wear a harmless piece of paper.
If they didn't want a run on masks, they should have chosen to say something other than an insult to our intelligence, and then backtrack. And if you don't believe that the CDC, WHO, journalism outlets, were begging people to not wear masks back in February, I have to wonder what rock you've been living under.
What should have happened was "masks work, here's an approved pattern you can make at home with just some cloth, and we're nationalizing PPE production and distribution for the time being; please know that's so the healthcare workers who may save your lives can stay alive".
I'd like to see steps taken to increase the independence of organizations like the CDC from the political world.
I'm sorry, but yes it is.
First off, those are not common-sense issues. They're complex, and just because they make sense to the high IQ crowd on HN doesn't meant that they have any reflection on common sense. Just because anti-vaxxers say that vaccines are bad because "common sense" doesn't mean that it has anything to do with other than them being morons.
Common sense is that masks do something and aren't harmful to use. Common sense was right. Just because common sense and intuition are sometimes wrong doesn't mean that they're always wrong, which would be a fallacy. It doesn't even take common sense; an average joe can use basic cost-benefit analysis to decide whether to use a mask, if they are wondering whether a mask is a good idea. Trusting people(often pundits) with ulterior motives over a month after the fact would have turned out to be less advantageous.
This idea that we can't ever use our intuition because it's often wrong is dangerous. If we can't make any decision with intuition, including one as harmless as wearing a piece of paper over our faces, then we're slaves of the mind.
This makes perfect, intuitive, common sense to a significant portion of the population.
Including health experts:
"...depending on the vaccine formulations used and the weight of the infant, some infants could have been exposed to cumulative levels of mercury during the first six months of life that exceeded EPA recommended guidelines for safe intake of methylmercury. As a precautionary measure, the Public Health Service (including FDA, National Institutes of Health [NIH], Centers for Disease Control and Prevention [CDC] and Health Resources and Services Administration [HRSA]) and the American Academy of Pediatrics issued a Joint Statement, urging vaccine manufacturers to reduce or eliminate thimerosal in vaccines as soon as possible. The U.S. Public Health Service agencies have collaborated with various investigators to initiate further studies to better understand any possible health effects from exposure to thimerosal in vaccines."
https://www.fda.gov/vaccines-blood-biologics/vaccines/thimer...
To this day thimerosal is not included in childhood vaccines, except for some flu shot formulations.
Placebo-controlled, double-blind clinical trials have never been completed to evaluate the safety of thimerosal. Partly because it would be unethical to inject a known toxin into people to determine it's safety.
If these trials had been done, and health authorities were convinced it was safe, they would allow thimerosal in vaccines because it is a huge cost saver. But instead, through the actions they took, they made it clear it is not worth the risk.
As an environmental engineer I've witnessed this tactic over and over. Authorities claim there is no evidence of danger, but remove the toxin anyways, because they know it's danger is plausible, and the funding and time isn't there to prove it one way or the other. Absence of evidence is not evidence of absence.
It's not like they are going to say, "we think we may have poisoned people, so we're removing this toxin." That's a great way to destroy your livelihood, reputation, and invite prosecution.
The safety of thimerosal is entirely possible to evaluate. It was in a bunch of childhood vaccines; it now is not. Has there been any demonstrable difference?
> But instead, through the actions they took, they made it clear it is not worth the risk.
Not necessarily. Could just not be worth the fight with the anti-vaxxers spreading bullshit about it. See also: Subway ditching azodicarbonamide because some blogger started a scaremongering movement around it.
If you don't believe that proper clinical trials are important to evaluate safety then there's not much more I can say. Epidemiological studies are rife with problems and the data can be manipulated to claim almost anything you want.
"Not necessarily. Could just not be worth the fight with the anti-vaxxers spreading bullshit about it. See also: Subway ditching azodicarbonamide because some blogger started a scaremongering movement around it."
Good point, but mercury is one of the most toxic substances known to man, does not break down, and is scientifically proven to bio-accumulate in mammalian tissues and never leave. It was also injected directly into the body, bypassing all the normal biological defenses a compound must go through before entering tissues. Furthermore, people can chose to not eat Subway without consequence. If vaccines had thimerosal in them again, it would be unavoidable without major life changes and being forcibly removed from large swaths of civil society. A consequence so severe necessitates a more proof than just saying you think mercury is safe in small doses with zero supporting concrete evidence.
Thimerosal was removed around 2001, well before the anti-vaxxer movement had enough influence to matter.
Your feelings and weak suppositions about thimerosal in vaccines are not science, and rather just indicate that you want to believe what you want to believe without presenting any concrete evidence.
We know hand sanitizer can be carried in our pockets and easily and immediately used when we are at risk.
Once again experts lied rather than getting distilleries and other factories to ramp up production.
Soap and water is better than hand sanitizer. If you have access to it, it should be preferentially used. Sanitizer is great for "I just got to the car after grocery shopping".
And I don't recall anyone saying face masks were useless when worn by people who were already ill.
They were, however, saying you don't need to wear it if you don't have symptoms, despite clear evidence of asymptomatic transmission.
No, they actually aren't. The "this won't be a big deal" response resulted from a combination of conditioning(things were relatively safe for a long period of time), learned helplessness, and the MSM telling everyone that "it's just the flu". There were even pundits laughing at "crazy people" wearing masks for "just the flu".
You're right, nobody said that(that I'm aware of). What they did say was that masks weren't effective for people not showing symptoms(unless if you are caring for a sick person), which is wrong on multiple levels. Even if you aren't showing symptoms, you could be shedding the virus, which was known months ago, hence a mask would be appropriate even for someone who isn't sick. There's also no evidence that the virus and the droplets that carry them are exempt from the ability of any kind of mask to filter things out of the air. If a mask is only 25% effective against the virus, that still means the person wearing a mask is less likely to get sick.
All it takes for the common person to make the rational choice is a cost-benefit analysis. If the greatest cost of putting on a mask is that the mask does nothing and they are out a few bucks, then it's better to buy some masks ASAP and wait for a good reason not to wear them rather than letting their trust in authority gaslight them into believing the sky isn't blue.
Exponential growth is hard for people to grasp.
But we also need to use our brain.
Even when trying to use my brain, I have troubles understanding how droplets can distinguish the direction of passing through a face mask, i.e., how my face mask can help protect others from my droplets, but how it cannot protect me from other people's droplets.
Well, I do understand that if the holes are too large, it will not be a 100% protection, but I do not really understand how the direction would matter.
That said, preventing a run on masks is important if you don't have enough, because some people need masks more urgently than others. I am convinved that in order to prevent a run on masks, you cannot just tell people the truth, but you need to lie to them, because many (or most) people will still get a mask if they know it is actually somewhat helpful.
Masks don't necessarily completely stop all the droplets, but the ones they let through are slowed down, which means they fall to earth at a much shorter distance than unimpeded ones.
Incoming droplets that doesn't matter all that much - they only need to go a few millimeters to reach your face. Outgoing droplets, though, need to go six feet before they hit someone if you're practicing proper distancing.
https://www.latimes.com/politics/story/2020-03-20/disaster-f...
If you operationally define "good" as "fewer dead people" then reserving what masks there are for healthcare workers and first responders is a "good" because they are society's agents that can save people from death.
Not enough masks? Doctors nurses first on the lifeboat folks. That's just the way it is.
Sure, telling people not to buy them is a poor substitute for what ought to be individual conscience. How is the fact that such a substitute has to be sought "their" fault ?
Micro droplets suspending in air https://vimeo.com/402577241
https://www.who.int/emergencies/diseases/novel-coronavirus-2...
• If you are healthy, you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection.
• Wear a mask if you are coughing or sneezing.
• Masks are effective only when used in combination with frequent hand-cleaning with alcohol-based hand rub or soap and water.
• If you wear a mask, then you must know how to use it and dispose of it properly.
Nowhere do I see: "Masks don't work".
[1] https://www.who.int/emergencies/diseases/novel-coronavirus-2...
"Masks don't work" being short hand for "masks will only help you in these very narrowly defined circumstances."
It's a folly that will be remembered and looked back negatively in history. One of many poor decisions by people in power.
https://twitter.com/Surgeon_General/status/12337257852839321...
https://www.vox.com/recode/2020/2/13/21128209/coronavirus-fe...
"Currently, the Centers for Disease Control and Prevention (CDC) advises against people in the US using face masks because most people who aren’t trained medical professionals may not know how to fit them properly, and the risk of exposure in the US is so low to begin with."
[1] https://twitter.com/c_drosten/status/1241659738569539584 [2] https://www.spiegel.de/wissenschaft/medizin/corona-krise-die...
Yes, if you read between the lines the statements were often hedged, and not strictly speaking wrong: you should not wear masks (because healthcare workers need them more), masks dont protect (you) from coronavirus, there is no study that shows masks protect against the novel coronavirus (specifically). The general public just reads that you should not wear masks, period.
Some people experienced hostility for wearing masks in public. You can get laughed at or coughed at. Asians wearing masks are avoided like they have the plague. And an old lady sneered at me (no mask) for keeping the required 2m safety distance in the supermarket, as if I was an idiot.
That being said, most people are behaving exemplary and respecting physical distancing, and I hope the attitudes regarding masks will shift with time.
I pumped both fists in the air and exclaimed "we're not dead yet!" and she laughed.
You live in a big city perhaps.
"Seriously people- STOP BUYING MASKS! They are NOT effective in preventing general public from catching #Coronavirus."
The US Surgeon General, a little over a month ago.
At this point, I don't think anyone is really arguing that "masks don't work." Dr. Birx is worried that people will see masks as a substitute for other measures like social distancing, hand washing, and avoiding touching your face.
There is a growing "grassroots" movement advocating that everyone wear homemade masks -- #masks4all
Makes sense not to wait for the CDC on this on. Every day makes a huge difference.
See https://shouldiwearafacemask.com for a summary.
Yes, it's becoming an untenable position now.
People were taking a very different tone a month ago with "we should all be wearing masks when out" suggestions.
Hell, a week ago, HN was happily flagging pro-mask stuff off the front page with regularity.
Just one point, but I have an interesting observation here:
Earlier this week I finally found some masks, and last night wore one to the grocery store for the first time. It's about a 10-minute walk each way, and I encounter 5-6 dog-walkers in that distance.
Usually the dog-walkers don't bother with social distancing, but while I was wearing the mask about half of them went out of their way to go around me.
But overall, it helps signal to everyone that you are taking precautions seriously.
And the more people who wear masks, the less stigma there is associated with wearing them.
The macro impact can be huge:
"If 50% of the population were to wear masks, only 50% of the population would be infected by the virus. Once 80% of the population wears a mask, the outbreak can be stopped immediately." https://www.researchgate.net/publication/258525804_Testing_t...
It's also something that will need to be mandated to have an effect. Authorities are all too happy to order workers to stay home and create incredible hardship for themselves, but ignore common sense measures like mask usage.
They are NOT talking about N95 "masks". There is constant confusion in the press and elsewhere between these two.
One protects others (surgical mask), and one protects others AND the wearer (N95).
Vox proposed that we call N95s by their technical term, "respirators", and other masks "masks", but then I suppose people will start confusing "respirators" and "ventilators"
Maybe you didn't mean it that way, but that sure sounds pretty absolute to me.
> They are lytic in nature and are among the smallest viruses, with diameters of about 30 nanometers. By comparison, other viruses, such as smallpox and vaccinia, are around ten times larger at about 300 nanometers; while flu viruses are around 80–120 nm.
The smaller the virus, the easier it slips through a mask's fibers.
Yes, of course it has an effect. Why do you think health care workers wear them?
Because they will be closer than 6ft to infected people.
This all depends on the type of mask and how tightly it fits against one's face.
A mask made from cotton has been shown to be ~70% effective at filtering a virus from droplets in the air: https://www.researchgate.net/publication/258525804_Testing_t...
2. Asymptomatic coronavirus cases don't know they're not healthy, so mask wearing protects others from those people.
Last comment on that I heard from CDC interview by WSJ: "patient becomes contagious either after symptoms appeared, or right before that (couple hours)".
And using common sense, if a person doesn't cough or breathe hard with air droplets, then they must be way less contagious naturally.
Larger particles called droplets carry most of the virus load from any particular sneeze and are what cause most infections that don't involve hand to face contact. They send to only go 2 meters in talking and sneezes into an elbow but they can go further in an uncovered sneeze. A surgical mask should be generally protective against these getting into your mouth or nose but your eyes are still vulnerable to being infected this way.
There are also smaller particles called aerosols that linger in the air for longer but don't travel very quickly. A much smaller fraction of the virus particles in a typical infected person's exhalations end up in these. In this case a surgical mask will only stop 4/5 or so of the particles you would otherwise breath in - better than nothing but not to be relied upon. In dealing with Coronavirus patients doctors and nurses usually rely on something called an N95 mask that's guaranteed to stop 95% of any sized non-oil particle and in practice seems to stop something like 99% of particles like a coronavirus. These are especially important for medical professionals because some procedures, like the intubations many Covid-19 patients need to survive, tend to cause way more aerosols than normal.
In terms of protecting others surgical masks seem to be a bit less protective with aerosol transmission for outgoing air than incoming air. I would guess because potitive pressure causes surgical masks to puff out a bit and leak more while negative pressure improves the seal. In the one study I've read on the matter it was a 1/3 difference which is noticable but they still make a big difference. More importantly surgical masks seem to stop outbound droplet transmission. On the outbound side the fact that someone's eyes aren't covered will also be irrelevant and someone wearing a mask won't have their droplets land on surfaces causing later hand to face transmission.
Wearing a home made mask is a lot like a surgical masks but a bit less likely to stop aerosols.
For the overall result, Ian Lipkin in a recent interview mentioned a study done in Beijing where they found that people who regularly wore masks were 70% less likely to get SARS in the original outbreak. That's nice but isn't anything like being invincible so measures like social distancing are still important.
If you've got a N95 masks then please give it to someone who's going to be doing things like intubation where it's aerosol stopping power is critically important and just wear a normal cloth mask otherwise. Remember that if your mask stopped some incoming virus particles those particles will still be on the outside of the mask and treat that danger with respect.
As for shortages that's a logistical failing that should be corrected before next time. Like how about require that first aid kits contain 5 masks.