Here’s the final verdict on the untainted CDC report issued 10 years ago:
“The use of fabric materials may provide only min- imal levels of respiratory protection to a wearer against virus-size submicron aerosol particles (e.g. droplet nuclei). This is partly because fabric materi- als show only marginal filtration performance against virus-size particles when sealed around the edges. Face seal leakage will further decrease the respiratory protection offered by fabric materials.”
Here’s the whole report: cloth face masks. 
What remains unclear is, why the big push – after telling us not to wear masks, now we are mandated to do so?