Why will most Australians get a less effective vaccine?
Australia's on track to get access to or to approve two different coronavirus. Vaccines is one from fayza. Biontech and there's one from oxford strelka but the two vaccines are quite different defies. A shot has like ninety five percent efficacy based on the studies and the oxford. One has a lot less than that. But it looks like we're only gonna get enough of the fiso one to vaccinate maybe five million people it's going to be prioritized for the people who are most vulnerable kind of everyone else is gonna get the oxford one. So we've got simony questions from people and a lot of them. Cluster around the question of why most australians going to get a vaccine that looks a lot less impressive than what we know is possible when it comes to fighting corona virus country. I just wanted to chain. Just want to alter one thing that you say. Is that the head of the therapeutic goods administration before christmas indicated that in fact they were going to get data from johnson and johnson from their vaccine. So this is not one of the vaccines that the government's got an arrangement with but i think they've made a preliminary application and all the last forty eight hours. The ceo of johnson. Johnson has said that they're going to be releasing their phase three trial data in the very near future. Now this is an adenovirus vaccine which is one which called virus. If you'd like carries the corona virus spike into the cell. A bit like the astro vaccine and the chinese vaccines. But it's a one dose vaccine rather than a two doors vaccine so really interesting vaccine. It'll be really interesting to see what they come up with this. This the johnson and johnson one and we'll possibly be another option. The tj seemed to save before christmas that this was on the table for approval which is interesting even though we haven't got a business arrangement with them as far as we are led to believe. Okay so let's just recap on the data the pfizer the moderna and the astro vaccines all do the same thing. They take genetic messages into the cell and tell the cell to produce the spike protein which then goes off into the blood and the immune system responds and create an immune reaction which is then memorized for future infections the pfizer and moderna one dude by mini which package of genetic messaging and the astra. One does it with a chimpanzee virus. Adenoviruses takes into the cell and leaves the genetic message there behind to produce the spike protein. So they do the same thing but in different ways from the trials the phaser moderna vaccines have you around. About ninety five percent efficacy. Let me just explain. The word efficacy for a moment. Efficacy is a word used in trials clinical trials which shows the in the trial context in the circumstances of that trial where the included and excluded certain people and the duration of what they monitored. That's really what efficacy means. Within the context of trial they got ninety. Five percent efficacy at reducing disease. If you were infected there were not enough data from those two trials at least not yet to show whether the affected infection and transmission although with the astra trial they did actually have datta which did suggest that the astra vaccine prevents transmission. Which makes us pretty confident that the pfizer. We'll actually resist transmission tube but we have no data on that yet. So it's efficacy. It's not effectiveness in the real world so when you introduce a vaccine or a drug into the real world. The efficacy may change. It may go down. It may go up and that will be seen as we monitor it going through. Okay so what did the astro vaccine find it. Find that when you gave to standard dozes roundabout four weeks apart thereabouts. You got sixty two percent effectiveness at reducing disease all disease and much harder effectiveness reducing severe disease so all these vaccines seemed really good at preventing severe disease and death but the oxford overall sixty two percent effective. The seventy two percent comes from an average and really shouldn't be used because it's not relevant average because the smaller british trial made an error and gave a smaller dose to some people who raised under fifty five and then give a standard does later and what they got was ninety percent effectiveness in that small. Subgroup wasn't planned but they noticed there and when they put those two together. That's got seventy percents so it's not a fair comparison. Comparing standard does to standards to those standards especially younger people might be less likely to have severe disease anyway. Yes so that makes sense biologically because what's happening. Almost certainly with the astro vaccine is that the body is developing antibodies. Nobody absolutely proven. But it's actually ironically and sort of sadly developing antibodies to the chimpanzee admiral virus so the very virus that's like an uber bringing the genetic basis into the cell. The body's reacting to that so when you get the second does the second dose isn't working as well because the body's working against the actual vaccine vaccinated against the vaccine so that makes sense with the low dose because you haven't generated as many antibodies to the chimpanzee virus there for you get a really good prime with the first low does and then a good hit with a second does now there's indications that came out of the same is true of india and a sense from the ceo of astra that the results are better than you think. And the implication was that if you separate the two standard doses by three months you might get sent effectiveness now. We talked about it a little bit but that on yesterday's corona cast 'cause that's a long time between dozes and as we've seen just talking about the uk variant. We talked about the brazilian various african very very unfair to them by country. But that's the shorthand version of doing it. We're getting a quite quickly of new variants and three months between vaccines might be too long and that the virus changes between dozes and. That's the problem there.