Yet.....they don't disagree. That is why masks are widely used throughout the medical community. Your laymen's understanding is they disagree.Yes, the mask study was from 2015.
However, they said it was for 'flu" viruses and specifically said the corona virus is even smaller virus size than the flu. thus, the masks would be even less effective with the covid-19 than flu sized particles.
I guess what my point to you is, their are studies (scientific ) of masks done by alleged credible sources, and those fuckers cant agree. So, how do us NON scientist people know the truth, other than picking a side?
my opinion is, based on all these 'credible' fucks that don't agree on shit, my thought is the "science" is BS at best when they can't even post clear results within their own community. Its all fuzzy math in the end. which means, there is really more opinion to it all, than actual science.