You can't follow? Wow. Okay. Let me try to simplify: Death rates of a virus can be mapped over time. Given enough time and deaths, rates can be calculated for people of all ages and demographics. However, once a virus mutates, all bets are off. From what I've read, COVID-19 is relatively stable, but there is no such thing as a guarantee. Just an educated guess.
Hope that helped.
No. It didn't help. As for the coronavirus, from what I have heard, 7 new strains of it have mutated into existence in the U.S. and probably Europe. I also saw about a paper that came out of China recently. Though it has yet to be peer reviewed. According to it, scientists there have identified 30 new strains of it that have mutated into being. It would seem that the coronavirus is far more prone to mutation than the flu virus.