> It's the overwheming consensus among medical professionals. The CDC recommends masks, as I linked. "Consensus", without evidence, is just opinion. Tragically

> It's the overwheming consensus among medical professionals. The CDC recommends masks, as I linked. "Consensus", without evidence, is just opinion. Tragically for the credibility of science-based policy, the evidence backing these mask recommendations is incredibly weak. That's just a fact. Repeating to me that "scientists say" something-or-other to be true does not change the fact that the evidence backing the claim is poor. Medical science is riddled with examples of interventions that "medical professionals" recommended without evidence, only to find that they were ineffective -- or worse, harmful -- when a controlled study was finally performed. Just a few recent examples: hormone replacement therapy; aspirin for heart disease; widespread opioid use for pain; mammograms under age 50. All were "overwhelming consensus". All have been since found to be useless. Some have led to tragic outcomes. The CDC and the WHO could have run randomized controlled trials to find out of n95 masks are effective at preventing illness. They did not.