Here's a good article about the mutation issues. To answer the earlier question about where they came up with the 70% figure, it's based on modeling the growth they have observed. So yeah, while kind of interesting, take it with a grain of salt.
The New York Times: The Coronavirus Is Mutating. What Does That Mean for Us?.
https://www.nytimes.com/2020/12/20/h...n-variant.html