It seems conclusive that cloth masks reduce the number of virus particles being inhaled and exhaled, and so theoretically they should work. See Fig 3.A here. h

It seems conclusive that cloth masks reduce the number of virus particles being inhaled and exhaled, and so theoretically they should work. See Fig 3.A here. https://advances.sciencemag.org/content/6/36/eabd3083 https://advances.sciencemag.org/content/6/36/eabd3083 I understand we also want RCTs to show that they actually reduce infections in practice. But, I will note a few things here. It's almost impossible to study via RCT whether their usage protects other people from infection, which is one of the goals of masks. The best we can do is go with our knowledge that it does block aerosols from being exhaled and use common sense to then assume that this means that it also will protect others from getting infected. Also, it could be the case that while it may not prevent infection, it reduces the severity of the infection due to a much lower viral load being inhaled. This is a difficult question to study. In all, we need to see larger studies done in locations where there's more cases. That one RCT in Denmark isn't enough.