John Campbell has a nice (but a bit lengthy) break down about it.
John Campbell's commentary on the Covid pandemic has been excellent and a source I've returned to repeatedly since I discovered it fairly early on. Clear-spoken, understated, research and facts based, tends to usually go along with concensus, though he will break on occasion where newer evidence or experience suggests advice is flawed, and there he's typically been right.
If he flubs a fact or point, he typically addresses that at the top of the next video.
Not selling anything.