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

https://www.cochrane.org/CD006207/ARI_do-physical-measures-such-hand-washing-or-wearing-masks-stop-or-slow-down-spread-respiratory-viruses

by rippercushions • 3 years ago

17 33 3 years ago

cochrane.org

superkuh6• 3 years ago

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.

blindriver3• 3 years ago

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.

taeric7• 3 years ago

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.

taeric7• 3 years ago

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.

superkuh6• 3 years ago

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.

ccn0p2• 3 years ago

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.

Scalene23• 3 years ago

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.

readthenotes1• 3 years ago

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

Scalene23• 3 years ago

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.

mmastrac2• 3 years ago

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."

rippercushions2• 3 years ago

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.

mmastrac2• 3 years ago

That's not what the study says at all.

robertheadley2• 3 years ago

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."

rippercushions2• 3 years ago

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.

Scalene23• 3 years ago

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.

pella• 3 years ago

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

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

blindriver3• 3 years ago

Conclusion: No hard conclusion can be drawn.

cameldrv• 3 years ago

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.

robertheadley2• 3 years ago

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.

kthejoker2• 3 years ago

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.

ksaj• 3 years ago

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.

richij• 3 years ago

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.

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

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