What We Can't Know About a Vaccine

country may see a coronavirus surge by Christmas. Merkel said today that Germany will face more than nineteen thousand new COVID nineteen cases a day by the end of December if the current trend in infections isn't halted. The country recorded about eleven thousand cases last week. Merkel told leaders of her party that the country must act quickly to avoid the same rapid rise in cases as neighboring countries such as France, which has been reporting an average of

about twelve thousand cases each day. Moscow has started to reopen temporary hospital wards after daily coronavirus infections in the Russian capital Sword. The capital is the epicenter of the virus in Russia. City Hall ordered eight Moscow hospitals to re equip themselves to handle patients by early next week. According to the inter Facts news service, Moscow began demobilizing

its temporary wards in late May. Finally, Hong Kong's latest coronavirus wave is showing signs of subsiding after months of social distancing measures. The country posted single digit increases in cases for seven of the last eight days. That has pushed the rolling seven day average daily infection rate down to about five the lowest since the end of June. And now for today's main story, the race for a

COVID nineteen vaccine entered a new phase. Recently, four different vaccine candidates developed by Moderna, Fiser, bio ent Tech, and Johnson and Johnson entered final stage trials, with two others close behind. But we won't know exactly how these four

vaccines work for months. I spoke to reporter Robert Langrath about what we can and more importantly, what we can't know about a vaccine developed at breakneckt speed give us a broad overview of some of the major differences among the front runners right now in the race to develop a COVID nineteen vaccine. Yeah, so there are a variety of different vaccines that are now in the final state

trials in the United States for COVID nineteen. Two of the vaccine front runners are so called a messenger RNA vaccines. And those two vaccines that use that very new technology messenger RNA are the ones from maderna US biotech company and from the big drug giant Fightser, and they are both very far along and testing and could have results early results from a phase three trial trials plural in

a month or so. They're both two shot vaccines. Most of the first vaccines are two shot vaccines, meaning you'll get you'll need to take two shots of the vaccine spread out over three or four weeks in order to potentially have some protection from the virus. And then the third vaccine that's in final stage trial now in the US is a vaccine that's based on a cold virus called adnovirus that is from astro Zenica and University of Oxford,

and that that cold virus based vaccine. It's based on a monkey cold virus that basically can't replicate in the body but helps bring in the coronavirus spike protein in and in the fourth vaccine in final stage trials in the US that is also based on adnovirus, a type of common cold virus. And again, UH, this is one that's been altered so it cannot replicate in the body. And that's the J and J vaccine, and that just began final stage trial in the United States and other

countries on sixty people. And the big difference with this vaccine is that J and J says and may be able to have efficacy with just one shot. So this is gonna be the first attempt at a single vaccine UH in the United States. And the advantages of a single shot vaccine is of course just practical distribution and immunization mass immunization advantages. Okay, So among these four front runners, obviously everyone is keen for the same goal that their

vaccine is effective. But in terms of the trials that are going on right now, how exactly does one prove

that a vaccine is effective. So all these trials are a placebo controlled trials where a participants healthy volunteers in the trials are randomly assigned to either get the vaccine or a placebo shot, and then they're basically followed after they get their shots for weeks and months to see how many patients that got the real vaccine got the coronavirus COVID nineteen versus how many patients they got the

bacebo vaccine at the coronavir IRUs. And the hope is UH that these vaccines will reduce the incidents of symptomatic COVID nineteen by at least half. That's the hope. That's the goal of the trials are hoping to do more than half, but the kind of half is sort of the minimum, the bare minimum that the Food and Recondministration

has said it would accept. There's some controversy over whether the trials, in a rush to get results, in a race to get sooner, are including UH and counting in the trials, you know, patients with you know, relatively mild or moderate cases and not focusing enough on the more severe cases and the kinds we all want to prevent, the hospitalizations and I see you visits and the deaths UH, and that kind of data will take much longer to collect.

But what they may get early on in the trials, they may get a sense of, you know, how it prevents UH somewhat milder cases and mild moderate cases and may not know as much about what it does in terms of preventing hospitalizations or I SeeU visits, because those, of course are very severe events we want to prevent, but they're much rarer. And how about how these studies can account for, say, diverse populations that a vaccine will be effective, and say the elderly or communities of color,

how is that taken into account. Maderna actually slowed down one of the company's Maderna actually said it slowed down enrollment of its trials a little bit in order to make sure, you know, increased minority representation. I made an effort to do that now. Of course, another issue is that the coronavirus, as everyone knows now, is you know, most severe in the elderly, and that's where you know,

most of the deaths are occurring. Is what I don't think anyone wants is a vaccine that does a great job offending mild cases and young people, but you still have the deaths and elderly people. That's, you know, a

nightmare scenario. I don't think anyone wants. So they're trying to enroll those people, and we don't just won't know yet when the early results come out, you know, how much we'll have in terms of detailed results in older people, we may you know, not have all that information because if the trials, you know, are stocked based on kind of early results and symptomatic cases in the large your population the trial, it may not have those kind of all important subsets to how well does the vaccine do

an elderly population. Let's talk about accountability. You mentioned the requirements of the FDA has put out. What kind of data do these drug makers have to provide to say that their vaccine is reliable and safe and ready to be used. Yeah, well, they certainly have to provide a data to the FDA, and there's sort of there's sort of a basic minimum requirement that the vaccines be at

least you know, effective and preventing symptomatic COVID. But how do you define the symptoms and how mild a case do you kind of include for a point of counting.

The FISER trials is I would say the most controversial among researchers because it includes for the purposes of counting coronavirus cases for its primary goal cases and with patients have a positive test and just one symptom, so that could include you know, a lot of my potentially a lot of milder cases, and they could declare a success

based on that. And then some top researchers are worried they might declare success based on you know, mostly milder moderate cases and not have many cases that are severe, and we won't know how well it works in the all important severe cases. So there's a great worry about that. But one of the consultants we talked to estimated that neither FISER number DIRTA would be likely to have results

in the more severe kind of hospitalization type cases. Really until February, they won't have you know, data, clear cut data on that. And it looks like other early results may come out as soon potentially as soon as the end of October for FISER and probably more like November sometime for MODERNA, So you know, it looks like there could be decision made on an emergency authorization of vaccine based on some of the kind of early results in

the trial. And it's not really clear how much we're gonna know about whether the vaccine early on really prevents the severe cases severe complications. It's just it's really unclear at this point. So what are the risks of pushing through an experimental treatment too fast? Yeah. One one big issue with any vaccine UH as safety, right, because there's a big, big difference between a vaccine that might be given to millions of healthy people, including younger people who

aren't at severe resee complications. So there's a big difference between a vaccine like that's given to very healthy people and a drug that's given to coronavirus patients already in the ICU. UH. And so in terms of side effects, UH, generally, you know, researchers want a lot a lot of data on safety. The question is, you know, how much is enough? Uh.

These trials are large. You know, there are thirty thousand people or more, and so that means at least, say fifteen thousand people get the vaccine, fifteen thousands get the placebo. But in the past, vaccines have been felled, are even

recalled for pretty rare side effects. These things can pop up and then you know, they may be you know, things that could occur, even severe events that could occur, even like one in ten thousand and so the researchers I talked to said that you know, based on a trial with thirty patients, we may know about things that happen you know, one in a few thousand, we may not know about you know, rarer events, a rarer adverse events that could happen because of vaccine, you know, until

later on to more and more people start using it. Uh So, you know, safety is something that really needs to be looked at, you very carefully. And already there's has been this controversy with the Astrosennica vaccine over a possible neurologic adverse effects that we're seen in one patient in the UK that Assnica says in University Oxfors says

aren't related to the vaccine. But that's led to the trial being on hold in the US while the US authorities trying to get more information about what happened in this case. What will we be able to know about how effective that vaccine is and perhaps more importantly, what won't we know? These trials are basically essentially going to show, you know, short term efficacy, because that's that's all we're

gonna have. We're not going to have much information on how long does the protection last, and of course that's a really key factor. To now is you know, how how how long are these vaccines gonna work? And we're just not going to have that information early on. And of course, the history of coronavirus is the cold, common cold coronavirus and other ones, is that the immunity to them is your fades over time, over you know, months to a year or more, a fade. That's why you

keep getting common colds again and again and again. Uh So there is a precedent for coronavirus is an immunity you know, not lasting a long period of time. And that's a really key question. It's like, are you gonna need to be reimmunized like a once every six months, once a year and nobody knows that and we're not

going to know that when the vaccine comes out. All we're really going to have is relatively short term ethicsly data that hey, so far, for a couple of months, this thing, you know, seems to work or at least partially. So that's a really key question that we just there's no way we're gonna be able to know that what a vaccine has brought out, especially if it's brought out early on this fall, based on pretty short term follow up that was Robert Langrath, and that's it for our

show today. For coverage of the outbreak from one hundred and twenty bureaus around the world, visit bloomberg dot com slash Coronavirus and if you like the show, please leave us a review and a rating on Apple Podcasts or Spotify. It's the best way to help more listeners find our global reporting. The Prognosis Daily Edition is produced by Topher foreheads Jordan Gaspure, Magnus Henrickson and me Laura Carlson. Today's main story was reported by Robert Langreth. Original music by

Leo Sidrin. Our editors are Rick Shine and Francesco Levi. Francesca Levi is Bloomberg's head of podcasts. Thanks for listening.