At this writing, there is a recent surge in widespread use by the public of facemasks when in public places, including for extended periods of time, in the United States as well as in other countries. The public has been instructed by media and their governments that one’s use of masks, even if not sick, may prevent others from being infected with SARS-CoV-2, the infectious agent of COVID-19. A review of the peer-reviewed medical literature examines impacts on human health, both immunological, as well as physiological. The purpose of this paper is to examine data regarding the effectiveness of facemasks,...