The fda is getting ready to authorize a third covid vaccine emergency use in this country. This one this vaccine is from pharmaceutical giant. Johnson and johnson. And if it's authorized it would join vaccines from pfizer and madera in the us vaccination campaign. But here's the thing those other. Vaccines require two doses. This vaccine from johnson and johnson needs only one single dose to be effective. Npr science correspondent. Joe palca is here to tell us how effective good morning joe morning. well one dose. that's exciting. How good is this new vaccine. Oh it's good. It was sixty six percent effect of overall in preventing moderate to severe disease and eighty five percent protective against more severe diseases. Now for people with good memories. They'll say wait. A minute i heard that madonna and pfizer wasn't that closer to ninety five percent effective and the answer is yes they were higher but those vaccines were tested before. Some of the new variants began circulating and prevent any five percent of severe critical. Disease is really good since the goal of the vaccines is to keep people out of the hospital and keep them from dying and the other thing about this vaccine is mentioned in the intro is that it's one dose which makes the logistics of getting it to people a lot easier to remember to come back so public. Health officials are looking forward to being able to distribute the j. vaccine. This is how anthony fauci chief medical adviser to the president. Put it on. Nbc's today show to have them come in and be in the mix with the other. Two is is nothing but good news. Nothing but good news. Foul cheat now. The process usually is before a vaccine gets authorized in advisory board has to approve it right. Well yes well. Though he has to is probably an exaggeration. It doesn't absolutely has to. The fda can approve things on its own lookout but like the other two vaccines. The the fda wanted to be extremely transparent. There were some questions about whether they were rushing the vaccine to the market before they knew it was safe and they want to assure the public that this was being looked at carefully so that committee has been around for a while. it's known in the trade as burg. Pack the vaccines and related biological products. Advisory committee i love that name ver- pack made of scientists and doctors with a variety of specialization relating vaccines before the meeting. Fda provides the committee with its analysis and they also make that analysis of the public So i asked. Bruce gallon president of global immunization at sabin vaccine institute. What he made of the analysis of the johnson and johnson vaccine. I didn't see anything in it. That i would think is going to be a show stopper for packed. Wanna recommend that. Fda act on so gallon is predicting the ver- pack will give the vaccine a thumbs up. How many doses. Johnson and johnson have ready to ship out. Well not as many as people had hoped a year ago when started trying to make these vaccines they all said. All we're gonna do this at risk manufacturing which means we're going to start making vaccine before they even knew it was going to be authorized even if it worked. And then they'd throw away if it didn't work and the government gave the money to do this but even with that company's still don't have the kind of inventory. The country needs in the case of johnson. Johnson they have about four million doses ready to go out the door and expect to have twenty million by the end of march and one hundred million by the end of june and remember. This is a one dose vaccine so one hundred million doses is one hundred million people vaccinated which is very big. Deal leslie and briefly. What is the timeline here. When the fda issued the emergency use authorization it could be any minute. I mean they knew it right after the meeting. They could do it tomorrow. That could do it in a few days. It'll be soon. I think if the committee gives a thumbs