learn in school. >> that's a really important point. the cdc's recent isolation guidance, meanwhile, is advising people who have recovered from covid-19 that they can stop isolating after five days but should avoid being around what amounts to, as you just heard in elizabeth cohen's report, more than 80% of the u.s. population. does this guidance make any sense to you at all? how are we supposed to know if someone is depressed or if someone used to smoke, for example? >> wolf, it's easy to criticize but hard to do better. when the cdc talks about being close to people who have elevated risk, they're not talking about passing someone on the street or being in a supermarket next to someone. they're talking about going over to someone's house, they're talking about socializing with someone at length. someone who you may have a prolonged period of sharing enclosed air with. and this is an example of cdc needing to communicate better. my view is that their isolation