Most of the results are unfortunately either by association (like the linked study), or on the spread of droplets without checking for infectivity. This means t

Most of the results are unfortunately either by association (like the linked study), or on the spread of droplets without checking for infectivity. This means that the evidence is still circumstantial. There are indications of efficacy, but not how large this efficacy is. I don't think masks are useless, but I'd love some hard data on how effective they are.