One observation related to this:
States that have seen clear declines in new cases tend *either* to have had either a LOT of cases early on (e.g. NY, LA) or very FEW cases (e.g. MT, HI). The states in the middle (e.g. MD/VA) aren't seeing much, if any, decline, conversely.
States that have seen clear declines in new cases tend *either* to have had either a LOT of cases early on (e.g. NY, LA) or very FEW cases (e.g. MT, HI). The states in the middle (e.g. MD/VA) aren't seeing much, if any, decline, conversely.
Why is this? If you're a state that had LOTS of cases then two things happen:
1) People are scared so social distancing is stricter and people abide by it more.
2) Some nontrivial fraction of your population is likely immune, at least for some period, which helps at the margin.
1) People are scared so social distancing is stricter and people abide by it more.
2) Some nontrivial fraction of your population is likely immune, at least for some period, which helps at the margin.
Conversely, if you're a state like Hawaii that never had many cases to begin with, it probably means you have some intrinsic geographic, etc. advantages that keeps transmission low. Also, with a low absolute # of cases you can do much better contact tracing, which helps a lot.
I think we need to think/worry about the large group of states (and countries?) that get stuck in the middle. Too many cases to do good contact tracing, too few to sustain as much support for distancing (or get any appreciable benefit from immunity) and no clear exit strategy.
