Free to read.

https://www.wsj.com/articles/w...11357072626796154883

If I can find the link I will attach it here, but there was another intruiging article about where the mutations are coming from, physiologically speaking.

The researchers found some suggestion that immunocompromised people may be associated with the mutations. The logic is this: for non-immunocompromised people, their bodies are able to attack and ultimately destroy the virus in short order. But for immunocompromised (which include the "long haulers"), the virus isn't successfully cleared from the body in the usual 10-14 days, giving the individual virus more time to mutate rather than be destroyed by a more highly functioning immune system.

While mutations are spontaneous, their ability to be viable requires a host.

I thought that was interesting.

Here's a brief, readable analysis