Ineffective Response to COVID-19 and Risk Compensation

"Do you think that almost all COVID-19 infections occur by face-touching, and almost none by droplets directly landing on someone's face?"

Not almost none, but very few, yes. Aerosol transmissions are a thing, but for non airborne transmissible diseases, these seem to be rare compared to close-personal interaction transmissions, such as direct hand contact and touching other people or shared surfaces.

EDIT TO NOTE: I have changed my understanding of this. The problem was that I misunderstood terminology - papers saying there is not "aerosol" transmission don't include droplet transmission via droplets that float in the air for up to an hour, from potentially several meters away, which I misunderstood.

Mask usage is great for reducing the rate that already sick people infect others, but not recommended for healthy people, because it's just not that effective. Sick people should be quarantined, which is far more effective. Perhaps 100% compliance with mask wearing would be a viable secondary measure, if there were sufficient supply for at least sick people (there aren't even that many,) and if it were plausible to be fully compliant - but mask usage is necessarily impossible when eating and when drinking, which people need to do routinely, and hand-washing if going to be still useful and particularly critical at those times. (And no, homemade masks aren't as effective, and masks shouldn't really be reused.)

EDIT TO NOTE: Because presymptomatic and asymptomatic transmission is a thing, mask wearing is likely useful to prevent transmitting the disease to others. It's still not clear that there is any benefit for healthy people, but since we don't know who is healthy, that's basically irrelevant.

I posted in to the EA forum, and have now crossposted that to Lesswrong. (I clearly overestimated the proportion of people who read both.)

Regarding transmission reduction from handwashing, two points. First, reducing $R_0$ flattens the curve in ways that make the epidemic far more manageable for emergency services, saving lives. Second, prior to any social distancing, the R_0 was far higher than it is when we have the growing norms around reduced hand-contact, etc., which could very plausibly combine to push $R_0$ far closer to 1.

After researching this for another 40 minutes, I still don't see where this claim comes from. All studies that I found are talking about adherence in the form of "was wearing the mask most of the time", and I can't find any analysis that wearing a mask is super complicated, and that people are wearing the masks in an ineffective way (many sources say that it's hard to get people to wear the masks at all, but that's a different issue). 

When you gave a group of people a set of masks, the people who comply to the level of "are wearing the mask most of the time" appear to be experiencing a significant reduction in infection rates. This is true even if the masks weren't fitted. Here is one of the variety of studies I found about this. 

I currently don't believe the "masks worn by people who aren't trained to do so aren't effective" claim. I also further believe that the effect of masks on untrained people is on the same order of magnitude as hand-washing (though definitely smaller, my gut says something like a 4th to a 5th as effective), and as such is not marginal. Though the latter claim is definitely not super well-sourced and I haven't done the appropriate fermi estimates, and would greatly appreciate more evidence on the relative importance of these interventions.

There is research on loosely fit mask like surgical mask effectiveness compared to fit respirators, and they are much less effective. My model here is that loose fitting masks that prevent 50% - or even 95% of the particles from reaching your mouth is near-useless if someone sneezes on you, since you don't need more than a very small number of particles to infect you. And otherwise, masks for non-sick people aren't accomplishing much without handwashing after every time they touch the mask - especially when people still touch their mouths behind their masks, as people often do even when they know they are aerosolizing dangerous pathogens in labs. To reinforce this, anecdotally, biosafety lab workers go through training, and still need routine retraining to make sure they wear masks properly and don't do things like eat with masks on by moving the mask out of the way.