The 3-4 month periodicity developing for C19 deaths measured globally suggests that vaccine effectiveness is actually less than 5 months

 Peak COVID-19 deaths per million measured globally occurred on Jan 26, Apr 29, and Aug 26.

Which means we should be prepared for another peak at the end of November or December.

The step-down pattern established so far, however, suggests deadliness is indeed on the decline, giving the lie to the Delta, aka the India variant, being qualitatively different.