Transcript for COVID-19 travel ban
And president Biden is now banning travel from South Africa over concerns about the variant there and Ream posing a ban. And some two dozen other countries ABC news contributor doctor John Brownstein is here to unpack it up for us. Doctor Brownstein how concerned are you about these areas from the UK South Africa Brazil. And will the new travel bans help especially considering the UK variant is already here. Yeah thanks and I hate. Think how. Our concern about these are certain they are building she agents here seem to be more transmits water Dickey is 70% more transmissible. And now are these new small. Short and more deadly disease are now we should we are welcome back to begin are you choose this on small sample sizes. They also the Croatian. Systems are over. But you're. Here be all and overwhelm our. It is all because it limits the numbers mean urged. Well we should. Bread and dairy farmers. Are. Due in limited are doing mr. emerged. We should implement in. The range we're seeing so. Shouldn't there. Although our words are we are. Here an. I and a good vaccine. The concern is a huge war does that mean and so the it was a good morning how old cheaper that's the best thing our I want yeah. Well let's talk about that availability because the CDC says I think it's roughly 41 million doses have been distributed nearly 22 million. Have been administered and yet some states are temporarily can't singling appointments right now. Saying they don't hobbled enough supplies in stock so what's going on with that. And then how much does the fact that Johnson & Johnson now says their phase three trial will be out soon. How critical is that to trying to improve this rollout finally getting things where they need to be. Yes I'm a Little League. I'm confused but some easiest because as a group that runs when these platforms and is easy leaders could amount of visibility I think part of the issue isn't so climate change and getting the vaccines the places where there's a mandate public health. Systems are well overrun and so there are pockets that are extra vaccine and places that don't and that's why we just focus on what are only just six. But yes supply is super important to exchange vaccine and the data coming which are so hopeful and today we heard it murder -- their backs into garnish and T center really are exciting candidate out of the mix with a little bit more pressure and changing records. AstraZeneca. Exciting changes that it's a one shot vaccine which neatly agency so much easier also in terms of storage so we don't fully know how supply and changing how soccer of course. Any amount well how in the current situation. And you said supply is super important but the CDC director said this week she doesn't know. How much supply the federal government has in the currently approved vaccines the Press Secretary in the from the White House to. Echoed that today so how is that possible first of all and if they don't know what the supply is how can they figure out how much to give each state. Yeah I think you. A little bit of an exaggeration because you know being looked at the scene immediately we know that there is. What has been distributed we know what's been injected I think your important data -- seems to always report are that he's in real time so we don't have full visibility. It's beautiful picture but I do think that we have a sense of where interests are how and where there issues in Michigan back seeing British we know that hostels you have access supplies he gets Walgreens are trying to get its act now tomorrow term care facility is probably receiving second doses but I think overall it's it's a slow counting in the data so we just need to improve the ordination of how between states and error correction because without that you can. Identify Reuters counts and each right now they're just and so sought to limit eighteen occasions that of course there's a lack that disability and without a disability we CDs obstacles over governor Robert and time tactic John Brownstein always great to have you thank you. You.
This transcript has been automatically generated and may not be 100% accurate.