Source of 65% was president of major toronto hospital network (UHN?) asking more employees to get vaccinated. I've seen similar numbers thrown around from various LTC facilities. Herd immunity percent was from memory and may be off, it should be easy enough to find 100 articles on it and then you need to decide which one was the most scientifically rigorous as I'm sure it is a range not a specific threshold that works every time. Variant creation isn't based on an article, it is based on scientific certainty. Replicate something enough and changes happen. Some changes matter, some improve the situation, others make the situation worse. As long as you have rampant replication, you will be creating many variants. Vastly slow replication and you slow the speed of variant creation at the same time. If we get a new variant every 100 years, that's not so bad, right now we are in the ballpark of at least a handful of very problematic mutations in a year.