Interesting story, I wish it would be correct, and I hope it is. I do not have an epidemiology degree, but my understanding is that viruses mutate, some more readily than others, depending on its type, DNA s. RNA etc.
Smallpox, polio and other viruses that we vaccinate children with are very stable - don't mutate, which is why you don't get sick after the vaccination and other diseases being eradicated or close to. The flu virus mutates, that's why we need a new shot each year, and hope that it is the right vaccine based on best guesses and what lineages are most active in the other hemisphere.
Viruses can mutate to be more readily transmitted, more or less lethal and more or less stable. In general, a less lethal virus will survive longer.
A virus mutation that kills a host within hours, before having a chance to replicate and infect others, will cause the strain to die out very soon.
A virus mutation that does not kill the host but spreads rapidly, will infect many, and this mutation will survive.
A virus mutation that kills the host, but only gets deadly after a couple of weeks of virus replication, will result in both death and spread.
At this point, I imagine that we have strains mutating differently in different parts of the world as we are so isolated compared to how it was before most travel shut down. That the virus is mutating to a less deadly version in Italy is no guarantee for the same happening in the US. There is no mothership coordinating the virus mutation. My hope is that the virus would mutate to be less lethal and more communicable that would give us a good enough immunity against a more deadly strain that might come in another wave.
Just my two cents...