brandon clarke, the chairman of the emergency medical hospital and he joins us tonight, thank you a lot for coming on. >> thanks so much to having me. >> tucker: of course we have not imposed a nationwide lockdown, we have in some places. judging by the numbers that are available from those places, do you think it's doing what it was supposed to do, as a working? >> is a good question that i think we just don't know the answer to yet. we have to remember the lead time on this virus is very long. the time that people feel symptoms as five days, most will have a bye 11 days after exposure so we are social distancing experiments have not been the full duration that we need to see a change in the slope of the new incidence of disease. >> tucker: give us a sense purely from a medical perspective leaving out economic or social considerations but here in epidemiologist trying to slow the spread of disease. how long would a quarantine need to last to be effective do you think? >> they were two pieces. we would need to see the slope of the curve change, in this instance all of us waiting for thi