Live data from Hacker News

Face masks effectively limit the probability of SARS-CoV-2 transmission

science.sciencemag.org

51–60 of 387 posts

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#51
post #9

Earlier quoted context omitted.

My 2yo would like to sneeze on you and flip that anecdote on its head.

Parent of a 1.5 year old here. Can confirm - several colds. To the parent comment's point though, I haven’t had any colds in the last year where my daughter wasn’t sick first

They seem to have perpetual runny noses when they’re really young.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#52

This entire study seems to be centered around a theoretical, mathematical model, and I didn't see any attempt to actually validate that model. Basically, the authors seem to assume that the virus behaves according to their formulas, and show that under their assumptions, face masks work, but don't actually prove that their assumptions match reality - or did I miss something?

No you didn't miss anything - most people upvoting this didn't read anything more than the title.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#53

This isn't a study; it is a mathematical model [1]. > Here, we develop a quantitative model of airborne virus exposure that can explain these contrasting results and provide a basis for quantifying the efficacy of face masks. We show that mask efficacy strongly depends on airborne virus abundance. Based on direct measurements of SARS-CoV-2 in air samples and population-level infection probabilities, we find that the…

Half the articles on your list are tangential (masks make it marginally harder to exercise, ok duh). The article posted helps us understand why the viral concentration in the environment also impacts efficacy, it helps explain why some of the articles you posted see inconclusive results.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#54

N95/FFP2 seem to be very effective. I wish the media and government would have spent more time in educating people in things like how N95 masks work and that it isn't like a coffee filter. Even thought the pores are larger than a virus the masks are statically charged causes smaller things to get trapped. Many people don't know this but probably had an interaction with static electricity sometime in school and would…

The problem is wearing mask is annoying and uncomfortable. If I have to choose, I'll choose the increased risk of covid all the time rather than wearing mask.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#55

N95/FFP2 seem to be very effective. I wish the media and government would have spent more time in educating people in things like how N95 masks work and that it isn't like a coffee filter. Even thought the pores are larger than a virus the masks are statically charged causes smaller things to get trapped. Many people don't know this but probably had an interaction with static electricity sometime in school and would…

I’m not sure there was any popular doubt over the efficacy of N95 masks. The problem was rather getting one - marketplaces like Amazon restricted access to masks if you weren’t affiliated with a hospital. So you were left with sketchy deals and weird vendor sites. I suspect Amazon killed quite a few people over the last year by restricting access - supply scaled pretty quickly.

According to the data presented, surgical masks are still highly effective even after converting the scales to linear. Add social distancing on top, it is almost as good as N95.

And I very much doubt that N95 masks are effectively utilized by the general public considering how many poorly fitted masks I have seen over the past year.

Before the pandemic there had been several studies looking at the efficacy of N95 vs. surgical masks at preventing the transmission of influenza in hospitals. Most of them never got anywhere because it was soon realized that even doctors and nurses cannot be trusted to wear and change masks properly during the daily routine. Let's hope things have improved by now.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#56

Earlier quoted context omitted.

I’m not sure there was any popular doubt over the efficacy of N95 masks. The problem was rather getting one - marketplaces like Amazon restricted access to masks if you weren’t affiliated with a hospital. So you were left with sketchy deals and weird vendor sites. I suspect Amazon killed quite a few people over the last year by restricting access - supply scaled pretty quickly.

Unfortunately, a few of my friends fell victim to the Qanon conspiracy bandwagon and the fact that mask pore size is wider than the virus was heavily circulated as a reason for mask ineffectiveness.

That wasn't a Quanon conspiracy: that was misunderstanding that I saw plenty of mainstream doctors and other health professionals promote. What it showed is that either they were intentionally lying - which I kinda doubt - or that they were so confident in what they had heard that they never bothered to do any research for themselves. Just reading the relevant wikipedia pages carefully would have corrected that misunderstanding.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#57

A science study that only shows, as this one does, that face coverings cover the face is not very useful. The public policy piece is much more complex. High masking states did NOT do better on COVID than low masking states.

By what metric? By deaths per capita, my impression was the low masking states did worse, but I didn't rigorously check the data.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#58
post #34

Earlier quoted context omitted.

Virus particles do not travel naked in the air, instead they are colloidally suspended in liquid, both droplets and aerosols. So, if your filter catches the droplets and aerosols, which are much larger in size than the actual virus, the filter works.

Realization that somebody's droplets are getting into your mouth and nose makes one want to wear mask even after pandemic is over :)

You may want to check how much of your body weight is bacterial and how easy it is to exchange samples with others. Just own the things that make us human.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#59

As suspected, it's exactly a probability game. If there's few infectious particles sure to low concentrations (e.g. people distance or are outdoors), you would roll the 70% penetration chance fewer times, and result in very few particles reaching deeper into lungs too as the velocities are reduced. When very close to an active particle source, you'd roll the conditional probability dice many more times. The critical…

Yes. Crazy how hard it has been for people to get this:

Imagine a bulletproof vest with three larger-than-bullet-sized holes in it. Say you know someone is going to shoot ten bullets at you - would you not wear the vest because "the attack vector can fit through the pores"?

The point is people treat this as a binary 'safe' / 'not safe' switch, when actually risk is related to the distribution of exposure to dosage.

Re: Face masks effectively limit the probability of SARS-CoV-2 transmission

#60

N95/FFP2 seem to be very effective. I wish the media and government would have spent more time in educating people in things like how N95 masks work and that it isn't like a coffee filter. Even thought the pores are larger than a virus the masks are statically charged causes smaller things to get trapped. Many people don't know this but probably had an interaction with static electricity sometime in school and would…

I don't think people need to know how they work. They just need to know that those are what doctors wear and that they are very, very effective. And much better than a mask you make from ad hoc materials.

Once N95 masks became readily available and cheap, it was (and is) mysterious why people weren't being told to wear them to protect themselves instead of wearing whatever was at hand to sort of protect themselves and others.

Post reply on HN