This HND piece examines the latest research on the efficacy of masks, as a protective measure against SARS-CoV-2. Some interesting observational studies are discussed, including a "before and after" situation at Mass General Brigham. This is about as close to a controlled experiment as we are ever going to get.
I also spotlight an interesting animal study, and the opinions of some real experts—not the puffed-up government types who have been dominating the discourse.
Read the complete article.