Here is a hypothesis: Open states allow people to build immunity through multiple exposures to the virus. Closed states block immunity building so when the state opens up the virus runs wild. Farfetched? Not really. The rates of Shingles has gone up since most children are vaccinated against Chicken Pox. People were constantly exposed to Chicken Pox through their lives, with each exposure boosting immunity. A person with clinical or asymptomatic Covid could each come in contact several times over the course of the last year with an active Covid case. Subsequent infections would be asymptomatic but would boost immunity each time.