Poor old John Snow, the English physician who discovered that cholera spread through dirty water, was just one of many who died before their alternative explanations were accepted. No wonder then that modern doctors recoil from miasma theory or anything that resembles it. But if this sounds like progress, you may be in for a surprise. A new paper published by leading academics argues that the western medical profession’s centuries-long battle against miasma theory initially blinded it to the fact that Sars-CoV-2 was airborne. Unnecessary delays