These viruses didn't have characteristics of coronavirus. Variants appeared elsewhere, but mutations and spread started near the time when vaccines started to

These viruses didn't have characteristics of coronavirus. Variants appeared elsewhere, but mutations and spread started near the time when vaccines started to become widely spread. E.g. check nextstrain.org and see when alpha/delta start to mutate most and timeline of vaccines rollout. Also consider how much Pfizers efficacy has fallen. Would it have fell so much if it wasn't for mutations against evolutionary pressure from this vaccine?