Studies are clear though. This one found non-N95 masks filter 20-80% of particles. https://jamanetwork.com/journals/jamainternalmedicine/fullar...
It defies common sense to say that won’t help the wearer! We haven’t done challenge trials, but the burden of proof is on those saying that a material covering the face and which filters out 20-80% of virus sized particles somehow won’t stop viral infections.
The infectious dose of SARS-CoV-2 is as low as 10 viral particles and a single cough can release 123,000 viral particles.
If I shot 123,000 bullets at you, would you be happy with a shield that protected you from 80% of them?
At any rate, masks have proven to be incredibly effective, but the truth is that we don't know exactly how... common sense has not been particularly informative in understanding the spread of this virus.
You would on the other hand expect a 100% fatality rate if you fired 123,000 bullets at each person in a room. So your analogy is faulty.
20% to 80% of filters is not good enough in a healthcare setting since a provider may be in a room absolutely filled with virus particles.
In a public setting, 20% to 80% might be enough to limit incidental viral loads enough to prevent infection.
It's hard to define the effectiveness across a wide variety of settings a cloth mask might be used in.
It was kind of a way to make people with valves n-95 masks feel “guilty” for wearing them.
A low enough load is like a natural vaccination. You don't get sick, but you get some immunity. A high enough load and you can get the sickness very severely. It's a gradient, and masks help put you lower on that gradient than otherwise.
As long as it's even marginally effective (and evidence suggests it's more than marginally effective) then it is a good idea.
The filter masks like N95s (which are usable for all kinds of non-medical purposes like working around airborne particles of fiberglass or metal debris or whatever) offer a high degree of protection to the wearer as well.
Also, it’s important to realize that initial viral load makes a significant difference in how sick people get. Simply reducing exposure can therefore reduce how sick someone becomes.
While that was an early hypothesis, I'm not sure that has really been proven. A lot of the early data wasn't really "initial" viral load, but viral load when they presented in the hospital. That's not necessary an indication of initial viral load.
So, initial viral load is not COVID specific. Also viral load at first detection is a different yet important criteria for EBOLA, COVID, and other diseases. https://www.jci.org/articles/view/83162
Your paper is about viral load at diagnosis--not infection. Diagnosis happens after your immune system has been fighting a while.
The 1 vs 50 difference is known to be based in part on the innate immune system not just the adaptive immune system. Most of the time you don’t need to create specific antibodies etc. If only a single virus enters the body it’s likely for you to fight off the infection without noticing though with the downside of failing to develop long term immunity.
https://en.m.wikipedia.org/wiki/Innate_immune_system
The 50 vs 50,000 is a related though less proven idea. Extreme exposure can simply overwhelm the immune system and extreme cases directly result in septic shock, but the middle ground is harder to test.
Just try it for yourself, put a N95 on you face and don't even press the metal nose thing, and then see if you can fit a surgical mask better than this unfit N95.
This is another meme which needs to die.
I have, with a proper fit tester. If you use a half mask respirator with cartridges, sure, the rubber seal is better by default. However, most N95 masks I've seen in public are are the cheap rigid masks leaving large gaps all around the circumference, whereas the surgical masks/bandana cling to the skin better.
There is a non-zero cost to wearing masks. It is important to be able to make the cost-benefit analysis when deciding which mitigation to implement.
as far as the "human cost" of wearing a mask... grow up. Asian societies like China/Japan/Korea have been wearing masks forever and they're fine. Now that the consequences of spread are more severe (vs just plain old flu) it's time for this custom to spread more widely.
again, the hilarious thing is it's always adults who are so childish about this whole thing. Kids intuitively get it, just like they grasp a lot of the boomer issues that society is burying its head about.
It's so ironic that in modern society, the children are adults and the adults are childish.
This is a racist meme that needs to die. You would see some people wearing masks. By no means did everyone wear them. Not even close.
The only people claiming that mask adoption was common across asia have never spent significant time there.