Does hand-washing or wearing masks slow down the spread of respiratory viruses? | Hacker News Reader

Does hand-washing or wearing masks slow down the spread of respiratory viruses?

cochrane.org

You can say these meta-studies means masks and hand washing don't help for large populations and you're right. But it's not because masks and handwashing don't work. It's because people on average are too stupid or otherwise cranky to wear them properly (ie, fit and sealed) and consistently.

It's not hard to wear a sealed N95 consistently and wash your hands when you come home. But almost no one will do this for years long time spans. That's what these meta-studies of populations capture: human laziness and stupidity.

The only real way to judge this is by measuring experts, ie. hospital staff. They are well trained and you can expect consistent results.

Any studies that employ the population at large is going to devolve to nothingness because they won't be consistent and eventually over long periods of time, they will slip up and given how contagious COVID is, they will get infected. Then people can turn to the study and say "SEE! THEY DON'T WORK!"

If the study is focusing on the question "Does it make sense to tell the general public to wash and wear a mask?" I think that's a different question than whether or not masks and hand washing protect people.

Troubling here, I don't know a single medical staffer that did not get covid. So... I'm not sure this would give different results.

This is dangerously close to the arguments that you can write safe C code. Logically, that is perfectly true. Empirically, it is a non-sequitur.

If even experts can't avoid getting COVID, it means that regardless of how effective masks are, it's impossible to avoid COVID over a long time period. So the effectiveness of masks is moot, because the difficulty in its perfect use is too high.

I wouldn't take it quite that far. Given enough time behind the wheel, everyone will crash a car, after all. Doesn't mean we can't take measures that greatly reduce the severity and rate of crashes.

I mean... not wrong, but how good of adherence do you think you can realistically get? Especially knowing that we are also talking about school age people, too.

That is, I am very interested in how effective of an idea it is. If normal adherence can only get me a 5% reduction in risk, I can understand why I may not want to bother. If it can get me 50-80% reduction, that changes things in the other direction.

As such, I'm glad there are folks doing these studies.

I know how well I can adhere. That's all that matters. That other people act like children does not change the reality that well fit N95 mask and good hand hygiene works. You should not base your decisions off meta study based on false premises (ie, most don't actually mask up properly).

The article headline should be, "Can the majority of people act more responsibly re: infectious diseases than a kindergartner?" and the answer is no. And that only encourages me to keep it up.

As a criticism of this meta study, I think this is fair. As a criticism of the idea for knowing the efficacy of masks, this is shortsighted. More, comparing the majority of folks to kindergartners is... not helpful.

I trust you have managed to avoid getting sick period for your entire non-kindergartner life? Do you know how much "better" you would have had to have been to do so?

That's correct. I still have not been infected with sars-cov-2 three years into the pandemic. I haven't tested for the N protein immune reactivity in my blood or anything, but I have been extremely careful about exposure and rapid test regularly.

It's the same for my local family which also mask properly with N95. It is very possible to not get infected and infect others. So yeah, I will call people who refuse to wear masks kindergarteners having hissy fits.

I am on your side for the folks that refuse to wear masks. I am a bit less on that side for folks that have actual grade school ages in the family.

Note that we are a family of 6 and didn't test positive until a few months ago. That said, I did test negative for antibodies 6 months after whatever started the pandemic. And whatever I had back then was far far worse than what had us testing positive this go around. I can only assume that the vaccines do as desired, and that is what helped.

Which is all to say, patience and a bit more empathy goes a long way. I don't want to accept that we will all get it, that said, with how contagious this is, either you are also very good at isolation, or you are running a very real non-negative risk even with masking. Is a bit like driving. It can be done safely, of course, but the more you drive, the more you raise your risk. And at that point, it is more of a numbers game than is often comfortable to think about.

The risk to self for people that have children is certainly so high from the kids that wearing a mask in public doesn't really shift it one way or the other. But the other side of this coin is that if the parents don't wear masks in public spaces their risk to others is actually higher than a random person without kids because their children are so likely to get them infected.

So I understand the reasoning. But it's selfish and incomparably more rude than I am being. And it doesn't have any releavance to weather masks (and hand hygine) work or not.

If you are contagious, you are best staying home and not going out. Pretty much period. As such, if you have reason to think that you could give someone covid, stay home. Hopefully we have reached a point where folks are ok doing this when they are sick later in life. (I certainly hope we encourage folks to stay home when sick from now on.)

With the major caveat that we don't afford that luxury to the vast majority of workers out there. Instead we seem to push a narrative that if the worker does the right precautions, they can return to work with no risk in getting others sick. Which, just doesn't seem to pan out.

The majority of sars-cov-2 infections are asymptomatic and they always have been. Additionally it's significantly transmissive for days before symptoms happen when they do happen.

Down this path lies "always where a mask." Which I doubt even you are advocating for?

For hand washing, I'm comfortable with that. For the mask? Princess Bride quotes not withstanding, I don't see it happening.

And to be clear, for some things, where the cost of the preventative measure is essentially zero, I'm fine with this. Driving a car? You have to buckle up. Riding a bus? Things change. And that last is an important point. Nuance in policy is more than just "is there a risk" but also "does the mitigation of the risk encourage worse behavior?" If requiring seat belts on busses reduced capacity of busses and reduced ridership on said bus, with a corresponding increase in cars, that would be a bad decision.

Now, does that directly apply to masks? I don't think so, but I do think a ton of the energy that was being directed at masking would be amazing to reclaim if it doesn't work at the society level.

I didn't mean to imply I supported using physical violence (government regulation) to force people to wear masks in public buildings. I am only stating that those chosing not to are doing something that is at the minimum, extremely rude. Half of them are (not) doing it because they are lazy and life is hard, half are doing it because they're ignorant assholes. Both groups deserve a middle finger... but not a cop attacking them.

If N95 masks have worked so well for you, why walk around angry at everyone else for choosing not to wear them? You're in for a long life of anger and resentment.

there's theory, and there's reality. As mostly engineers here we'd love to live in theory, but that's not how the world works.

All of these studies continue to show that adherence is the key variable.

Of course in an absolute sense wearing mask, hand-washing, social distancing, etc. for a short period of time will marginally (even if microscopically) decrease your chances of acquiring a virus.

Just like brushing your teeth once absolutely reduces the amount of plaque on your teeth.

But it's adherence, over a long period of time which tells the tale of whether you get sick or have a cavity.

https://healthfeedback.org/claimreview/multiple-studies-show...

"Inadequate support: Claims that face masks are ineffective at reducing the spread of COVID-19 based on a Cochrane review didn’t take into account the limitations of the review. While many users presented this review as the highest-quality evidence, the individual studies it evaluated varied greatly in terms of quality, study design, populations studied, and outcomes observed, which prevented the authors from drawing any definitive conclusions."

This rebuttal is less than convincing. The core of the argument seems to be that a lot of right wingers are saying the study "proves masks don't work", which it doesn't. But it doesn't really address the study's actual finding, which is that we're not seeing evidence that masks work.

1. That is not what the study found. 2. The reason that there is limited evidence that masks work is that the effort required to collect more than limited evidence that masks work has not been undertaken.

Bangs head on desk. Cochrane is asking the wrong question (or, at least, too narrow a question).

This meta-analysis looks at efficacy of masks to protect the wearer. Whereas the primary need is to catch infected droplets before they infect someone else.

Conclusion: No hard conclusion can be drawn.

They used to post graphics that basically said masks only work if you and the infectious person are both wearing masks. In other words, if only the uninfected person is wearing a mask, or if only the infected person is wearing a mask, all bets are off.

Basically they all demonstrated that you need a mask to keep some of the infectious stuff out of the air, and another mask to avoid as much breathing in what the infected person's mask didn't filter.

I imagine that has not changed. It's hard to tell though because none of the subsequent tests seem to ever take that into account.

- https://theconversation.com/yes-masks-reduce-the-risk-of-spr...

- https://www.theatlantic.com/health/archive/2023/02/covid-mas...

It's good they published this, but it's effectively a zero for any data either way. They did manage to find a small benefit to hand-washing, but overall there's no way to judge mask use as a clear benefit or not.

"Evidence is limited by imprecision and heterogeneity for these subjective outcomes."

However, if there was a strong effect, it would have shown up in this study. So now we know that even if masks do "work", the effect is relatively small at best.

That's not what the study says at all.

This part in the section about limitations tells me that the only reasonable conclusion is that more data is needed: > Relatively low numbers of people followed the guidance about wearing masks or about hand hygiene, which may have affected the results of the studies.

how much more data do you need to know that many people wear masks on their chin and everyone takes them off in restaurants?

The question being asked: "Does hand-washing or wearing masks slow down the spread of respiratory viruses?" Your question has nothing to do with the question being asked.

Hardly any of their studies are about COVID. The virus itself as well behavior relative to the virus are very different. I don't see how this meta analysis adds any value to the question of the effectiveness of masks relative to COVID.

I asked Bing ChatGPT.

Are masks effective at preventing covid-19 infection?

According to various sources¹²³⁴⁵, masks can help slow the spread of COVID-19 when worn consistently and correctly, along with other preventive measures such as getting vaccinated, frequent hand-washing and physical distancing. However, some masks offer higher levels of protection than others². What type of mask are you interested in?

Source: Conversation with Bing, 2/20/2023(1) How well do face masks protect against COVID-19? - Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/coronavirus/i... Accessed 2/20/2023. (2) Types of Masks and Respirators - Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si... Accessed 2/20/2023. (3) Do face masks really reduce coronavirus spread? - Live Science. https://www.livescience.com/are-face-masks-effective-reducin... Accessed 2/20/2023. (4) Use Masks to Slow the Spread of COVID-19 - Centers for Disease Control .... https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si... Accessed 2/20/2023. (5) Mayo Clinic research confirms critical role of masks in preventing .... https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-re... Accessed 2/20/2023.

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