Hacker News new | past | comments | ask | show | jobs | submit login

I don't blame the professionals for getting things wrong on this.

My personal feeling is that it was hard to know if masks worked for the general populace before Covid-19.

There are so many confounding variables that it very difficult to study masks from a public health side.

The best approximation was studies of health professionals in hospitals or clinics which doesn't exactly translate for a multitude of reasons.




To be honest, we still don't really know if masks work. They look like they probably do something, but the evidence is weak and the effect size small.

It's totally worth it to bend an exponential function. But the individual benefit from mask wearing in any given interaction is negligible.


Which leads to huge arguments which really benefits nobody as we just establish that we disagree.

Common sense seems to say that masks make s difference, but if that is the strongest argument, then why not let people decide for themselves using common sense.


Mere common sense? I wouldn't characterize it that way.

The wearing of masks to combat airborne disease spread is a decidedly not a new thing. That was never a novel concept, at least since the early part of the 20th century.

Coronaviruses in general aren't a novel concept either; we have a pretty good idea how they're spread.

So, when confronted with a new coronavirus, it's a little bit stronger than "common sense" to surmise that masks will be effective to some extent. The burden of proof would be on anybody suggesting that this virus is somehow so different than other airborne disease that the wearing of masks had no benefit.

    then why not let people decide for themselves using common sense. 
If masks are not effective, the downside to wearing masks was that we waste a relatively modest amount of time and money on masks and perhaps damage our credibility in the future when we recommend their use.

If masks are effective to some degree, the downside to not wearing masks was that millions of additional people would suffer and die worldwide, and we would incur a financial and human cost orders of magnitude greater than the modest cost of masks.


Because if you get it wrong, lots of people die, so you err on the side of caution.


Common sense comes up with the wrong answer here. The individual benefit was likely very small. The cumulative effect over many weeks on buildup in cases is much larger.


Can you point me toward some of that research?


There's a massive number of studies. A selection of 3 links out of 100+ would only reveal my biases. I'd rather just discuss my summation of the research and if there's something in particular you'd like to see, share that.

* Various studies of droplet propagation, which show well-fitting masks reduce droplets significantly. In theory, this should reduce spread.

* Many confounded observational and cohort studies tied to voluntary compliance with mask guidelines that show a lower risk of infection or secondary transmission. They are confounded because voluntary compliance with this measure increases the likelihood of general caution. Many show somewhat large effect sizes.

* Many population based trend-line studies/other ecological studies that show post requiring it as a public health measure in various environments, that daily case counts began to decline by .4% to 2.0% per day.

The studies in the second category showing larger effects are generally inconsistent with the third category, because the results in the third would be much bigger if the effect was real. And even the third category isn't great, because the mask requirement measures weren't instituted in a vacuum independent of other controls.


Do the studies in the third category account for compliance?

I wonder if we’re splitting hairs, so what if mask wearing is confounded with other voluntary measures of general caution?

For me the take away is that some people take precaution, and some don’t.


One of the studies was an ecological study comparing mask wearing rates in many locales (some with compulsory requirements, and some without) and their change over time vs. disease growth rates.

Another measured case growth in a hospital community where there was a very strictly enforced mandate for patients compared to the rate of case growth before, so compliance is a small factor.

It's very likely that masks help. It's also very likely that the effect is relatively small. But even a tiny effect can become a big one when raised to a big power-- 1.1^20 is 6.7x growth in cases, and 1.07^20 is 3.8x.

I'd have liked this guidance change in masks to come a week or two later. Keeping another couple weeks of somewhat sharper decline in cases means a lot fewer people affected through the rest of the pandemic.


Your conclusions here don’t really seem in line with your comment about still not knowing if masks work.

Not sure why you feel like this is a worthy hair to split.

This kind of attitude is why the western response could have been better. Western medicine is hews rigorously close to the “do no harm” ideal and interpret it that you need to have conclusive evidence before recommending a treatment, even something as harmless as mask wearing.

In Asian countries they just do it and so what if it hasn’t been demonstrated as a causal factor in a dozen studies.

Lay people see the indecision, the hemming and hawing, the hand wringing.

The cdc says shit like people shouldn’t wear masks.

This shit is actively harmful and thousands of people have died because of it.


We have confounded evidence of a weak effect. If I had to bet (and we all have had to), I'd say they do have a small benefit on a population scale. But if more evidence showed up saying they didn't, I would be completely unsurprised.

I think it's worthwhile to have doubt and be skeptical.

I'll note that, at the beginning of the pandemic, I was saying that masks may or may not work, but they should still be recommended at a time that the CDC was implying that they might even be harmful.

This is all completely consistent with what I originally said: "To be honest, we still don't really know if masks work. They look like they probably do something, but the evidence is weak and the effect size small."


Part of the problem is that the American media spread misinformation about the effectiveness of masks for political gain. For example, I remember the New York Times pushing the idea that vaccines would be less effective than mask wearing even though all evidence suggested that even a vaccine which met the minimum standards for approval would likely be substantially more effective than mask wearing, seemingly because Trump supported vaccines but not masks.


There was a period in time where it was disclosed that the vaccines might have an efficacy of 40% or 50%.

In this case, the combination of masks and vaccines might have been required for a long time.

(hacker news analogy: "just in case Rust doesn't remove all defects, we are still going to need to debug"


    seemingly because Trump supported vaccines but 
    not masks.
I read both conservative and liberal media and have never seen it suggested that masks were somehow better than vaccines.

First I must strongly state that the idea itself makes no sense: one can wear a mask and be vaccinated; they're not competing ideas in any meaningful way.

However, at the outset of COVID-19, we certainly were not sure that there would be effective vaccines, or how long they might take to develop, or what their supply levels would be.

Therefore it made sense to take whatever (effective) measures we could, while waiting for a vaccine that was never guaranteed to exist. Nobody argues that a fire extinguisher is better than a squad of professional firefighters, but fire extinguishers can have important utility, especially while you're waiting for help to arrive.

As far as the Trump angle, perhaps you can show us a counter example, but I have seen zero evidence that anti-Trump folks have rejected vaccines because Trump favored them. It's a non-factor.

One, the liberal/progressive/whatever crowd is overwhelmingly pro-vaccination (in general) to begin with. Two, and perhaps more importantly, they're just not competing with masks in any way. Masks are imperfect; vaccines are more effective but also imperfect and not approved for all people even today. That is how you deal with many if not most threats in the real world: multiple layers of imperfect defences.


To be fair, doing the exact opposite of what Trump supports is a good rule of thumb if you have no other info or expertise to go on.

Though in this particular case, I don't really remember him being all that positive about vaccines for Covid or in general.

Here's a publication worrying about him undermining vaccines before Covid was a thing: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5678397/

Which is another data point to support the general principle.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: