b). I don’t know the re-infection rates well enough to say for sure. I’m not sure anyone does. The Louisiana and Arizona curves make me suspect second infections are kind of common. Both states show multiple peaks, a few months apart. That’s exactly what I’d expect if recovered people can still transmit once their immunity weakens. If second infections are common, then a post-covid dinner party is still a bad idea.
a). if everyone attending has been vaccinated, it’s probably safer. That one has at least been studied more thoroughly. Out of politeness, I’d still say that able bodied people should still socialize outside with the rest of us, even if they have been vaccinated. I don’t was to see compliance fall because those with early vaccines start setting a bad example.
Is it possible for AZ's second spike to be caused by snowbirds? Looks timely to me. They usually show up around OCT. They don't come alone, many bring immediate family for a short while. Snow birds of all colors - Upper Midwest, Midwest, Plains states. Their kids and grandkids help them move in, stay a week or so, play golf, eat out on patios, eat inside, etc....then they leave.
AZ is now trending down. In terms of ICU capacity, the second wave didn't impact any differently than the 1st wave - ICU bed capacity hovered between 90-92%. The big difference between the two was the many procedures were cancelled during the summer surge. this time around hospitals didn't cut as many procedures. They were able to manage. Razor thin margins with staffing but they have seemed to pull it off.