The concept of herd immunity leading to disease eradication is simple. More vaccines, less disease, right up to the point of everybody gets vaccines, no more disease. But that's simply wrong. It's not because herd immunity doesn't help decrease disease, but because the idea of herd immunity is based on too-simple math. We can all get the idea easily. In a homogenous human population, there should exist a level of vaccination at which no more disease can be transmitted. Notice the fatal flaw is not in the concept, it's in the word "homogenous." Human populations will never be like bricks or milk cartons. You can't just line them up and expect everyone to be the same. So the concept of hitting a magic point and having that point mean no more disease is a mathematical graph, not a human reality. But it's such a nice graph. You can see a version here . The more you vaccinate, the fewer cases. But if you look at that graph, you see something like m...