Your disposable cotton and paper masks are useless.
Even worse, the cloth masks that everybody is wearing are actually dangerous and facilitiate the transmission of KungFlu.
The only masks that work are "medical masks and respirators", as pictured below. Everything else is useless.
Published in the Journal of Clinical Infectious Diseases, Volume 65, Issue 11, 1 December 2017:
Effectiveness of Masks and Respirators Against Respiratory Infections in Healthcare Workers: A Systematic Review and Meta-Analysis
Conclusions
Our analysis confirms the effectiveness of medical masks and respirators against SARS.
Disposable, cotton, or paper masks are not recommended.
...medical masks are preferable to
cloth masks, for which there is no evidence of protection and which might facilitate transmission of pathogens when used repeatedly without adequate sterilization.
