Now the CDC is recommending masks not just for the unvaccinated but for the vaccinated too. This is supposedly because of the discovery that the variant known as Delta is making an end-run around the vaccines, causing not only infections but infectious spread. 

So we have an odd situation developing. The layperson's understanding of a vaccine is that it protects a person against infection, like measles or smallpox. In other words, you won't get Covid, exactly as President Biden accidentally and apparently inaccurately said in a press conference last week. That is apparently untrue in this case. That realization seemed to dawn on people only a few weeks ago, as reports from Israel revealed that half the new infections listed were with people who had been fully vaccinated. 

I pity anyone who took a few weeks' vacation from the news during this period. We went from believing that the whole point of the vaccines was to protect against infection to realizing that this was not the case. You can still get the bug. The point of the vaccines, we were newly told, is to protect against severe outcomes. Okay, that's reasonable enough except that we know the demographics of severe outcomes, and hence the question presents itself: why is the policy priority near-universal vaccination?