> There is no evidence to suggest community mask mandates slow the spread of COVID in adults.

This is, perhaps, the most frustrating statistic I've ever encountered.

N95 masks are outrageously effective at preventing the spread of infectious diseases, including Covid.

Mask mandates aren't especially effective because:

  * people ignore the mandates
  * the mandates aren't enforced
  * people wear their masks incorrectly
  * people take their mask off to cough, talk, eat, sneeze, neutralizing any gain they get from wearing the mask in the first place

I'm frustrated because there's nothing wrong with masks, it's the people that are screwing everything up for the rest of us.

Came to say this, thank you. There has been determined and successful effort to scuttle every public health initiative that was taken, so the lack of evidence proceeds from the lack of a test.

"compliance is low" is a common theme in health care. People don't take their meds, or they take the wrong amount at the wrong time. People put stress on repaired body parts when they are supposed to rest. Etc.

Public health normally incorporates this knowledge but I don't think the general public quite appreciates it.

Right. And that’s what we should also incorporate into the knowledge about masks.

But before putting too much weight on compliance, there are other factors that also lead to low overall effectiveness.

For example, the equivalence of mask types. There’s an explicit presumption that any mask is better than none. But it’s not a practical configuration that can lead to a substantial reduce in spread. So if getting infected matters, then we should educate that only the best (N95) will do. (And cloth masks are nowhere close to good enough.)

We should also not dream that compliance will ever be good enough to protect others. So optimise for where compliance can be controlled, right? (Of course this is “myself”, because I can control my own behaviour 100%, but others not so much, and there’s more of them.) We should have been saying “wear N95 to protect yourself, and wear it well”. Instead we let people labour under the impression that (a) they could wear just about anything, and (b) the onus was very much on others to protect you. And, of course, if you’re in a vulnerable group, that’s really terrible advice.

Basically we asked people to do something that was doomed to be ineffective. And when we factor compliance in, it shows up as not very effective at all. Instead, we should have asked them to do something very effective, and then the compliance hit would have been less.