Gato- I tested this theory of yours on just the local data set here in my county (~500,000 in size). Case curve and deaths curve had the 15 day delay the entire pandemic until Sept. 13. At which point cases broke higher but deaths detached and plunged. Coincidentally, 2 days after Biden’s mandate speech our first dose vaccine rate dropped 68%. What I observed is new first doses more closely trending with local Covid deaths than the cases. I have been looking for a reason why one county in my state with the highest vaccine % in the state did WORSE with Delta than the larger more-dense less vaccinated area.