UPDATE: CDC's stance on masks is evolving because our understanding of #coronavirus has changed. Some believe we should now view it like a poison, where the initial dose of exposure determines how sick you get. (This is different than, say, HIV). This feature of #coronavirus...

...makes masks more important & helps explain one of the most perplexing features of the virus:  #Coronavirus is now projected to kill up to 240,000 Americans (twice the number who died in World War I) yet 1 in 4 with the infection will display no symptoms. Why?

Many now believe the higher the #coronavirus dose, the worse the outcome. Like poison. This analogy may also explain why cruise ships are so dangerous & why so many healthcare workers are dying: they're exposed to high volumes of the virus.

Here's an excellent primer on the poison argument, and why masks are trending: https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html