tom: joshua sharfstein of johns hopkins. right now, i want to get right to this. futures up 21.tion is so important. robert murphy of northwestern, truly expert in the history and dynamics of infectious diseases, joins us this morning. both you and i were focused on michigan. i want you to go over the strange v-word, v irulence, and what we know of what is coming. robert: virulence is how effective it is in killing the host it is infecting. this has increased with this variant and the p1 variant in brazil. that variant somehow got up in canada, and british columbia, and they had to shut it down because of that. very difficult to deal with, as you can see what is going on in brazil right now, which is a catastrophe. tom: how do you deal with the viral and's -- with the viral and's -- with the virulence? robert: it is probably the reason we are having this wave, one of the main reasons we are having this wave, in that when we had these troughs where the case numbers have gone down, they have always plateaued. there's always been plenty of virus replicating before we have the next