I cover in this presentation the effectiveness of the different types of masks and face shields at protecting the wearer and at preventing the spread of COVID-19. You may be shocked to learn what the science has to say about this. The summary of that: N95 masks work best, face shields are great, then hospital surgical masks when it comes to protecting you the person wearing the mask or shield. Cloth masks are not providing proper protection. None of them offer total protection. Not for the person wearing them, nor for people around you (protecting the community).