[Mumps]

Oh come on.

A) nobody is making that claim - you are.

So don't turn this into some weird non-fact-based appeal to emotions. The claim that they are useless is because the evidence does not support them. They ARE useful in clinical settings, and heavily required there.

B) there is no evidence for their success:

1) https://www.bbc.co.uk/news/health-51205344 "implementing simple hygiene measures" was vastly more effective." "Although there is a perception that the wearing of facemasks may be beneficial, there is in fact very little evidence of widespread benefit from their use outside of these clinical setting." "routine surgical masks for the public are not an effective protection against viruses or bacteria carried in the air"

2)research study, particularly on leakage: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306645/

3) efficiacy in Beijin: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969371/ (again largely leakage)

4) efficacy in 22micron particulate: https://www.ncbi.nlm.nih.gov/pubmed/3470452 (again leakage. but depends on particulate size)

[jansan]

Nobody is making this claim? Since your nickname sounds German, you may be able to understand this text from the FAZ:

"Im Folgenden ist eine Reihe nachweislich falscher Angaben aufgelistet – etwa der Nutzen von Atemmasken gegen eine Ansteckung"

Source: https://www.faz.net/aktuell/gesellschaft/gesundheit/coronavi...

What they claim is that the uselessness of face masks is proven. Not that the usefulness is unproven. That makes a big difference.

[umanwizard]

For those who don't read German:

"In what follows, a series of provably false claims are listed - such as the use of breathing masks against contagion".

(Native German speakers can correct me if my translation is inexact)