bob walker the chair of ucsf's department of medicine dr. walker. we have some new data just out that shows just how effective the vaccine and even better the vaccine plus booster have been against hospitalization string omicron reich. can you give us those numbers? yeah, i tend to think of this in multiples of 10 that if you're compare someone if you're unvaccinated versus someone, who's that three shots, you have a hundred times lower probability of getting very sick on the hospital and dying so so someone who's fully boosted 100 times lower. booster versus two shots is about 10 times lower. maybe it's seven or eight but it's an easy number to remember that going from from your second shot to your third about a 10 times lower. of a bad a bad outcome going from nothing to three shots about a hundred times lower of a bad outcome. so people have had three shots really are tremendously safe particularly with omicron since it's a little bit milder, but you know a tremendous a very large advantage if you go from two shots to three as well. i was going t

bob walker to discuss the white house's move to overhaul the nation's covert strategy as we move out of pandemic mode. also, yesterday we had uc berkeley on to discuss how a lawsuit is about to force the university to have to reject thousands more applicants. today, the berkeley neighborhood group that brought the suit will be joining us. but first, the crisis in ukraine as pressure goes fulltilt with its assault. russian forces have today taken control of chernobyl, the site of the worst nuclear disaster the world has ever seen. joining is now to discuss the latest developments and the reaction from the u.s. and nato, director of stanford center of democracy, also the author of russia resurrected: its power and purpose in a new world order. thank you for joining us. >> thank you for having me. kristen: let's start with this. how well or not well is ukraine defending itself in its key city so far? >> i think it's doing the best it can with what it has. it's military compared to the russian military is minuscule. and it has culled up its reserves. it has a reasonable sized reservist a