COVID-19 infections are relentless. In every state, November rates increased over October, more than doubling on average. And these rates are widely dispersed across the nation. Early COVID-19 cases and deaths were associated with local conditions, including residential crowding and household income. More personal factors have since come into play as the pandemic spread and hotspots shifted to the heartland.
masks and COVID
Face masks and social distancing are the primary tools currently available for limiting the spread of COVID-19. The mask serves two functions: protecting the wearer by limiting the inhalation of airborne particles  and protecting others by reducing transmission of virus particles exhaled by an infected individual. This second role has not always been recognized nor well quantified. 
What exactly do we mean, scientifically, when we talk about individuals? ... Can a model of surgical care costing a small fraction of care in the U.S. teach us anything? ... Nassim Taleb writes about the use of masks. Some habits are hard to break, especially when we see them as the norm and not a habit at all.