Coronavirus (COVID-19): Press Conference with Barry Bloom, 07/20/20


You’re listening to a press conference from the Harvard T.H. Chan School of Public Health with Barry Bloom, the Joan L. and Julius H. Jacobson Research Professor of Public Health and former dean of the school. This call was recorded 11:30 a.m. Eastern Time on Monday, July 20th.

Transcript

BARRY BLOOM: I’m happy to answer and I look forward to answering questions. Today is an exciting day. There’s a new vaccine paper just published today in The Lancet. I’d be happy to chat about that, or the previous paper in the New England Journal. But any other questions that I am able to answer, I’d be happy to try.

MODERATOR: All right. Looks like our first question.

Q: Hi, thanks very much. I have a couple of questions about vaccines, if that’s OK. To start, I’d love to get your reaction to the Oxford-AstraZeneca data from this morning.

BARRY BLOOM: I was very pleased to see the paper, and quite pleased, but not surprised to see the results, which are certainly encouraging. After two shots, everybody produced antibodies that bound to the spike protein of this coronavirus, and also by multiple assays showed some degree of neutralizing activity. So, it produced the desired immune response, as best one could tell, from in vitro or a test tube studies. But, a lot of people in the trial had, at the highest dose, some mild, but irritating adverse effects. One of the interesting aspects was that a small group got the equivalent of Tylenol or acetaminophen, and that seemed to reduce significantly the minor side effects of sore arms and fatigued muscles. This indicates that they could probably run the next phase, phase three trials, and cause a little less discomfort in those who received the initial vaccination.

Q: Got it. And then, sort of more more broadly. One thing I’m trying to wrap my head around is how much progress is being made so quickly on the vaccine front. And I know they still have to go through efficacy trials, but still, we’re starting phase three trials for a virus that no one knew existed until about six months ago. So, I don’t know if this is fair comparison, but to think about something like HIV, which has been around for decades without a vaccine. So I guess I’m wondering, how, whether it’s the virus itself or new technology or just the sort of global efforts, what has enabled this level of progress this fast for this virus?

BARRY BLOOM: So, I have an understanding that this goes back a long time. And I’m not sure you want my view of history, but I will share it. After 9/11 and after the anthrax outbreaks in 2001, there was a meeting at the National Academy of Sciences that looked at the potential for terrorism and the vulnerability of the U.S. to both terrorism and things like natural pandemics. I co-chaired the committee with Joshua Lederberg on biosecurity. What we learned is this country was remarkably unprepared to deal with major bioterrorism or even things like influenza pandemics that we knew had occurred every 50 to 100 years.

Subsequent to that, this country created something called the National Pandemic Influenza Plan, I think starting in something like 2006, after we saw the potential impact of SARS, to realize that we were still vulnerable. A plan was created and updated multiple times, the latest being 2017, to deal with the anticipated threat of a viral pandemic, probably influenza. Clearly, no one anticipated the coronavirus outbreak. But we were prepared in the following sense, particularly with funding from BARDA, the Biological Advanced Research Authority. They decided at some point that it was really too time consuming to make vaccines as we have always made them.

The fastest vaccine ever made was mumps vaccine in four years. The longest vaccine was varicella. It took 27 years to get it licensed. And if we had a pandemic, we can’t wait four years. And so what they did is put up a request for proposals, creative ideas that create a vaccine against the new viral agent within 60 days. That was unheard of. Unprecedented. Yet that’s exactly what’s happened, both for this adenovirus, this chimpanzee adenovirus, and for the RNA vaccines. What was created is not individual, tailored, vaccines from scratch but platforms like RNA or adenoviruses or vesicular stomatitis virus ,VSV, or measles virus, where one could simply substitute an antigen for any new agent into a known host, safe or relatively safe vaccine platform, and thereby speed things up fantastically.

So, the Moderna vaccine was produced. From the time the cDNA sequence was published to the first phase one studies in humans, in sixty five days, meeting pretty close the criteria that BARDA had established. And other adenoviruses are on the way. The Brits had been producing this vaccine with chimp adenovirus against MERS and SARS, and had already done phase one studies for both of those. So they were in a good position to know what the adverse effects were likely to be. They understood and predicted that. Also that they would be relatively minor and likely produce good immune responses. The study published today confirms that on a larger scale. The next step really is to expand those to protect against infection and disease in the real world. And that will probably require something on the order of 15,000 volunteers to go into such a study. A longer answer than you requested, I apologize.

Q: No, I appreciate it. Thanks very much.

MODERATOR: Great. Next question.

Q: Hi. Thanks. I just wanted to ask on the death issue, obviously we’ve heard some theories or reassurances that deaths have not been rising as much recently. I just wonder what are you seeing in that kind of death statistics? I mean, are they rising again? Do you expect it to get just as bad as it was in April? Or is there some hope that it’s younger people now and we have better treatments and that sort of thing?

BARRY BLOOM: Well, it is clear that the death rate is rising. And as you know, death rates follow infection rates by something like two to three weeks. And so the question is, would it be as bad as it was in New York? And I think many of us are hopeful that it will not be for a couple reasons. One is, I think older folks like myself took our lesson from our vulnerability in New York, and many of those are staying at home to a greater extent. Which means, as you suggested, a larger percentage of people mixing with other people and being exposed, are younger people who are less likely to die. I think the second thing is, as long as intensive care units are not overwhelmed, clinicians have learned a great deal about how best to be able to care for patients, both in the intermediate stages of hospitalization and beginning to deal with them better as they require intensive care, and possibly intubation. We have a long way to go on new interventions for care. Remdesivir is a drug that may help the more severe forms of the disease. Dexamethasone may prevent the immune consequences that, apparently, lead to systems failure. So we’re a little better off now than we were in the New York outbreak in April. But, we are still hopeful there will be new drugs.

Q: Got it, thanks.

MODERATOR: Next question.

Q: Hi there. Thanks so much. My question is about distribution. I guess now, we have the Oxford vaccine, the Moderna vaccine, and there were results from China as well, that seemed encouraging. So, we have multiple potential winter vaccines, moving along. But I don’t really know, and maybe nobody does, how we go from there to obviously, demand will outstrip supply for some period of time, you know. Do you anticipate that it’s going to be a case of who can pay for it, gets it initially? Or do you see more framework in terms of being developed, in terms of getting, what European leaders are talking about as an equitable distribution? We haven’t done this before, right? Are we just gonna be making it up as we go along to a certain extent? Thanks.

BARRY BLOOM: I think you’ve asked a really key question, and there are two components of that worry me. The first and most obvious, that shouldn’t be obvious at all, is the scientific community is well aware of our tools for preventing the spread of this virus, other than complete lockdown, are really limited. Telling people to wear masks in public and indoors in public places, distancing oneself six feet away. Difficult to get compliance in the real world and particularly difficult among young people who really want to socialize. And it’s very hard to enforce. Those are the tools. They’re not terrific. They worked in China. They worked in Korea. They worked to an extent in many other places. They appear not to be working right now in several parts of our country. And that’s very worrisome.

The second question is, if we did have one or more vaccines, that was very safe, and effective, better than 50 percent, which is the criterion that will be used for phase three trials. The real worry here is whether people will take it or sufficient numbers of people will take it to provide the equivalent of community protection or what people call, herd immunity. And that is a worry nowhere else in the world, where I think people would be very happy to be protected against this virus. But, it is a continuing, and I think expanding, concern that many of us in the scientific business really worry about. And that is very difficult to deal with in scientific terms.

Having said that, the question that you’re asking is one that I am pleased to say people have begun to think about. I will, disclaimer, indicate that colleagues of mine and I have sent a paper to the New England Journal, which, hopefully they will consider, raising precisely this question. There is sufficient distrust of government scientists that somebody has to think very carefully about when these new vaccines become available. On January 2nd, there’s not going to be three million vaccines or five and a half billion vaccines to vaccinate every person around the world. How do we deal with a scarce resource in the fairest and most inclusive way? And there are a couple obvious possibilities. I think most people would say, possibly, that maybe those people who are most at risk should have highest priority. And who are they? Well, those are health care personnel; they’re residents of nursing homes; they’re people who are incarcerated in prisons; they’re African-Americans and Hispanics and Latinx individuals. How do we prioritize those groups who have traditionally never been prioritized for getting to the head of the line for health care?

An alternative way of looking at it is to say people in nursing homes die from this disease, but they’re not big spreaders of the disease. People in prisons are not big spreaders of this disease except within the context of their prisons. If you really want to stop spread, it may be the biggest transmitters are likely to be young people who congregate, who are not following distancing and wearing masks. Perhaps school children or teenagers, which we now know are quite good at transmitting infections that would be school age or university age people. That’s another target. And that’s what an epidemiologist would say would be the highest priority is to interrupt transmission. And vaccines are one way to do that. The question then is how do we make that decision? And our recommendation will be, it should not be made by the government.

There is so much politicization right now of everything from wearing masks to whether Tony Fauci, one of my personal heroes, can appear on television. That the decision of this prioritization for access to this very rare, in the beginning, commodity should be made by an independent group. Our recommendation would be the National Academy of Medicine, which has the capacity to bring together social scientists, ethicists and people from a wide variety of social and medical disciplines. They’re an independent agency. And if they were to do that, my recommendation would be this is something that requires a lot of community outreach, getting input from various communities, to find out where the public’s priorities are. And what would engender confidence that if you’re not in the first group, the fairest decision was made of those who it makes the fairest use of vaccines. So, that’s a long winded answer as well. But if this is not done well, if it comes from on high and the public is not part of that process, engaged, providing views, I think it will be even increased distrust in vaccines. That would be a tragedy if we want to end this epidemic or at least reduce it to a tolerable level a year from this year.

MODERATOR: Do you have any follow up questions?

Q: I do. Just a quick one. And thank you for that answer. I’m curious, given that there’s an international component to this, and a lot of these are being developed overseas. Are there complications in terms of approvals? I mean, China is an obvious one, right, because they have six in trials at the moment. And if they strike gold, I don’t know how that would get approved to be distributed in the US necessarily. But, does every country have to make their own decisions about which vaccine they think is safe to distribute? Thanks.

BARRY BLOOM: So the Chinese, I’m certain, will make their own decision. As you know, WHO has tried to organize the major European countries and have reached out to the United States without success to form a consortium of vaccine producing countries in the West. To set up guidelines that would enable sharing of whatever vaccines look promising, not just with their own populations in a nationalistic way, but to set aside vaccines in a way to protect not only their own people, but as the production of more and more vaccines occurs, to share those with developing countries that don’t have the capacity to produce vaccines at the millions and billions of doses required. I’ve worked for a long time for WHO. I have an enormous amount of respect for what they can do that no one else can do. Speed is not one of their characteristics. And I understand concerns about relegating the decisions on any national vaccines to an international body. The United States has not joined that EU coalition with WHO, so we will probably go our own way.

In terms of the Europeans, the Oxford group and the AstraZeneca vaccine that came out today, has already made arrangements with a very good high production capacity in India, the Serum Institute of India. So, they have already thought about having local production in India and Asia. We will probably have to have a debate in terms of priorities of how we provide vaccines to the international community. It would be, I think, a diplomatic, political and ethical problem or tragedy, if it was only used by prioritizing Americans. To let all the rest of the world either deal with other countries vaccines and not sharing with the benefits of United States science, that would be a great tragedy.

Q: Thanks so much.

MODERATOR: Next question.

Q: Hey, thanks for having me. Dr. Bloom, I know this isn’t necessarily your wheelhouse on testing here, but I have a colleague that is looking into the kind of obscene delays that we’re seeing down here in Florida, where we’ve really over relied on private labs. Test results are taking two weeks, I think, on average now. I just want to get your thoughts on this general problem. How do we how do we extricate ourselves from this over-reliance on private labs and this pool testing? The answer has been floated by the Trump administration.

BARRY BLOOM: What I have said in previous of these conferences with the press that I think is somewhat misunderstood, certainly by the public, is the testing is not the intervention that interrupts transmission of this virus. It is the isolation, or the quarantine, of people who test positive, and the identification of contacts and isolation of what would be required to stop trains of transmission.

Testing is only as good as people will agree to isolate, share the names of contacts they have been in contact with within the last 24 or 48 hours, and of those contacts who agreed to stay home for two weeks. I think that’s what I would feel really needs to be emphasized. When you have 7,000 new cases a day, there is absolutely no possibility, assuming between five and 10 contacts per case, there are enough contact tracers in the public health system anywhere to do 50,000 contact tracings, assuming people can give them information on who they contacted and that people will answer the phone call from the contact traces. So we’re in a real bind with contact tracing once the numbers get very large. I honestly don’t see an easy solution. More and more testing would be better, but the numbers are pretty overwhelming to identify all the contacts, get them to stay home. And after two weeks, hope that they no longer can transmit.

What gives me some optimism, in terms of testing, is new tests that are along the way. These are rapid tests. They will not be as sensitive as the PCR diagnostic tests that we use now. They will be cheaper, and a number of them may actually be able to be done by yourself in the household. I think we need to know whether they are sensitive enough. And I don’t know if the data, I don’t think any of them are published. How quickly they can be decided upon by the FDA recognizing their limitations in sensitivity, such that if a positive is found, you are very likely to have coronavirus infection and then contact tracing, isolation and all that makes sense. If you’re negative, it doesn’t guarantee, likely, that you are not infected and that poses some threat to the community. But something that can be done really rapidly, and people can do for themselves cheaply, seems to have a huge public health advantage. And if you’re thinking about opening up businesses, to have cheap tests that everybody that goes back to work in those businesses can do at low cost, has real advantages. We will miss a few spreaders that are asymptomatic. But if everybody who is asymptomatic that has enough virus to transmit is likely to be positive, and those that have only low doses of virus not likely to be very contagious, we would do very well.

So, I would think from the government’s point of view, and I know, the director of NIH, Francis Collins, is really pushing hard on this, I would hope that by the end of the summer we would have these low cost tests available with a sensitivity and likely to pick up those likely to be the biggest spreaders. And we’ll miss some that are low spreaders, but if they get can be higher levels and have the ability to test themselves every couple of days, twice a week, we will still do better than we’re doing with the molecular tests at the moment, at lower cost.

MODERATOR: Did you have a follow up?

Q: No, actually, I had a follow up and you answered it in your follow up, so I really appreciate that. And thanks so much. That was great.

MODERATOR: Great. Next question.

Q: Thanks so much for doing this. Going back to the studies out today, the second study was on a Chinese trial. I’m just wondering where you see the Chinese in pursuit of a vaccine? This was a phase two trial as opposed to phase one. Do you trust this data?

BARRY BLOOM: So that’s the adeno 5 trial.

Q: Yes.

BARRY BLOOM: That is moving forward in military recruits. I’d love to know what the informed consent forms look like. But nonetheless, there’s a real limitation to that vaccine. And that is adeno 5 is a relatively common adenovirus. Lots of people already in most populations have natural prior infections with this virus. It is likely to be limited in its effectiveness because the vaccine itself would be somewhat compromised by the immune response to the backbone of the vaccine. So it’s likely in those that did not have a antibody to be as good as the chimpanzee adenovirus that came out today, the chimp adeno was taken as humans have very little prior background, although even in that trial, one percent of the people in the trial had antibodies to this spike protein, which was quite interesting, probably indicating in the UK even healthy people had subclinical infection or asymptomatic infection. So, I think the virus is likely to be no better or worse than any other adeno virus. But worse in the sense that people will not respond nearly as well.

Q: They found, I think, a little over half had already had antibodies. I can’t figure out if they parsed out how those people responded versus everybody else. But they did have a pretty high response rate.

BARRY BLOOM: Yeah. They’ll make responses, but it won’t be as high as it would be for the adeno with two shots, I don’t think.

Q: And do you trust the level of research that’s coming out? This was a Lancet paper.

BARRY BLOOM: Yeah, I don’t know the investigators and the companies and the state agencies that are producing vaccine. I have a great respect for the scientists early on, and continuing in China who have reported everything on January 9th, the DNA sequence, January 29th, the case definition of what a coronavirus case looks like, that has informed doctors all over the world. I am grateful for those in Hong Kong University who did the first epidemiological modeling that predicted that no one had immunity to this and it was going to be a global epidemic of very significant significance. There are a lot of really good scientists in China, and it really is unfortunate that officials thought they could cover up an epidemic early on. Epidemics cannot be covered up. But I think from the announcements in China, they have been pretty transparent and the science has been awfully good. I think to see good science criticized on political grounds rather than scientific grounds is unfair and not helpful to all of us trying to deal with the epidemic.

Q: Thank you very much.

MODERATOR: Dr. Bloom, I had a quick question about that. Do you know why they might use a human adenovirus instead of a chimp adenovirus?

BARRY BLOOM: Because very few people were clever enough to figure a non-human adenovirus could be used instead of uncommon strains. For example, Johnson and Johnson and Janssen, the European part of that company, is using an adeno 26, which is a human adeno, but is very uncommon and has fewer antibodies than adeno 5. But for chimp adeno, the premise was that nobody would be likely to have antibodies unless they happened to cross react with some common determinant. So, it was a very clever choice by the Oxford people, Adrian Hill, for which I give them great credit.

MODERATOR: Thank you. Next question.

Q: Hi. I wanted to circle back. There’s a lot of optimism now over a vaccine, and I just wanted to give you an opportunity to kind of set expectations, since there’s so many of us on this call who are writing about this. We know that well, you know, that a fair amount of vaccine candidates fail in the late trials. So I wonder if you could just sort of talk about how optimistic should we be that there actually will be a successful vaccine out of these many candidates right now? And a rough timeline on when, I know you mentioned don’t expect millions of them or billions of vaccines on January 1, but please, please dig into that a little bit.

BARRY BLOOM: It’s very hard to predict which ones will prove to be the most effective. You can’t do that, you can’t even guess before phase three trials. For example, in the very limited number of non-human primates studies, it looks like antibodies to the receptor binding site on the spike protein that has the ability to block its ability to inspect cells in a test to provided protection against disease in rhesus monkeys. I would point out two things. One is it didn’t prevent infection. Now they were challenged with significant doses in the nose in the monkeys. What you would like a vaccine to do is prevent infection. So the monkeys didn’t get sick. They didn’t develop COVID. But rhesus monkeys don’t develop the serious adverse effects seen in humans in quite serious cases of COVID at the 15 percent of people who end up in ICUs. So it suggests that you may end up with a vaccine that doesn’t completely prevent infection, but may prevent disease or serious disease. That would be certainly better than we’re doing without a vaccine. But it would not be ideal.

The ideal would be a vaccine that prevents infection so that people who have it not only don’t have reduced viral loads in their respiratory tract, but have no infectious virus in their respiratory tract. And that can only be done in phase three studies looking at people who do get infected. There are ways that can be done to distinguish between whether someone is immunized to the s protein by a vaccine and has a natural infection. One could do that by looking at antibody responses to some other antigen in COVID, not in the vaccine. So, I think it’s possible to ascertain. Whether the virus prevents disease, which is what the trial is designed to do, but it’s also possible to prevent infection. And that would be ideal. The second is the only way to know how effective that is, is in a phase three study. That leads to another qualifier.

Both of these vaccines have been tested in healthy young people ages 18 to 55. That’s exactly the group that doesn’t have the highest rate of serious consequences, intensive care, intubation, and death. So, the phase two studies or phase three studies have to include vulnerable groups. A key one of which is people over the age of 50. Some of the vaccine trials that are being planned have scheduled for people over the age of 50 to 60, 60 to 70 and 70 to 80. And the other vulnerable groups that we don’t fully understand why they’re so vulnerable are African-Americans and Hispanics. They would have to be included in the vaccine, both to ascertain whether we’re all equally susceptible to adverse effects and whether we’re all equally able to be protected. That has to be included, hopefully, to some extent, in late stage phase two studies, but for sure, in phase three studies.

Q: Let me press you a little bit on the odds here, because, you know, I’m thinking of my mother. She’s going to ask me, are we going to get a vaccine? And she wants a one sentence answer because all the rest of this means nothing to her. So would you venture an answer to that?

BARRY BLOOM: Absolutely, for sure. And we will get more than one vaccine. I have to say that I read the guidelines from the FDA for the companies producing the vaccines for consideration of approval by the FDA. I will say I have been concerned that these emergency use authorizations for drugs like remdesivir were put out pretty easily. I would say without all the data that I would have liked to have seen. The UEA’s for the diagnostic, serological tests, non diagnostic serological tests, they approved 100 tests on what the company said they were able to do in terms of specificity, sensitivity that didn’t make any sense to me. And of course, they then went through the list and shortened it to those that had some demonstrable, confirmable sensitivity and specificity. So there was reason to worry that the FDA would take another shortcut on getting vaccines out quickly.

And I’m pleased to say I’m pretty confident that the guidelines that they put out are the same as they would be in rigor for any vaccine that we would make available to any healthy human beings in this country. I don’t see any shortcuts there. They’re going to propose very large numbers of people for phase three trials. They’re going to look at all the right things. They’re going to get data on adverse effects. If there was any concern that I have, it is that there is something after phase three called phase four studies, which are post licensure surveillance.

We’re looking for adverse effects that are going to occur in a phase three trial between now and January. And we’ll get, I think, good data on that for every candidate that the FDA will consider. There may be adverse effects that are longer to show up. That won’t show up in the first 15,000 people or in the first three months. And that’s something where post licensure surveillance that is simply following up recipients, asking them to report any adverse effects for the first year or two, particularly those who have been reinfected and whether having been immunized causes a worse response after reinfection. There’s no reason to anticipate that. But we want to measure that. That was made non explicit as to whether that was a requirement or voluntary. And it should be a requirement, in my view.

Otherwise, you can tell your mother that the safety and efficacy testing is as good as we’ve ever done for any vaccine. And you can also tell her that I thought if it’s as good as flu, which is 50 percent protective, I’d be pleased. I’d be a lot more pleased if it was seventy five or eighty five percent or even better. But we lose 16,000 people a year from flu and we have a vaccine that’s 50 percent effective. We could save a lot of lives. Even with a partially effective vaccine. And we will, I am confident, have more than one vaccine that achieves that endpoint.

Q: That’s great. Thank you for that. And I just want to clarify, you said absolutely, we will get a vaccine and now you’ve just said we’ll probably have more than one. Would you venture a guess on timeframe for when we would have a useful vaccine that is available to a lot of people? I’ll leave that kind of open ended for you.

BARRY BLOOM: I can’t answer that. I think no one really can, because this has to do with stuff beyond the skills and expertise of the scientific community that has designed these vaccines. We’re now talking about taking a safe vaccine that has gone through phase three, and producing hundreds of millions of doses. We know in the U.S., if it’s a one shot vaccine, we would like three hundred million doses. As of the moment, I don’t believe there’s a single company that can make a three hundred million doses. That’s one of the advantages of having multiple producers, because if no one producer has the scale to do everybody, we may have to use two or three vaccines, each of which is protective and safe. But each of which has a different company and a different capability of production. So the production capacity has to be very big.

What is extraordinary in this case, is several of the companies, AstraZeneca for the Oxford vaccine, Johnson and Johnson for their vaccine, are already committing to scale up to the hundred million to 300 million and possibly a billion doses. Investing in building a factory that costs literally tens of millions, if not hundreds of millions of dollars, before they know whether their vaccine is safe and effective. That’s never happened before. And that’s why things are being sped up. So several of the vaccines will have scale producers even before we know they’re safe and effective.

Once that is done, then I hope someone in the government, probably CDC, if it still exists after the current cutbacks, has to get each of the 50 states to be able to deliver vaccines to people who need it. And that requires a distribution system after it is decided, what is the fairest way and who were the highest priority people to get the vaccine to? We need probably a cold chain and maybe a sophisticated cold chain. For example, for RNA vaccines, we need a distribution system that keeps it cold, a reporting system to show who got it and whether there are any adverse effects that occur later on. All of that is a complicated business that is generally run through the national immunization scheme and state public health offices. And I don’t think they have been tooled up, at the moment, to deal with the possibility that it could occur by January 2nd. They’re going to be called upon to deliver those vaccines to people in a rational way.

Q: Great. Thank you, I appreciate all the detail.

MODERATOR: Dr. Bloom, it looks like this may be the last question for today. Did you have any final thoughts for us?

BARRY BLOOM: I think it’s very exciting to have two vaccines that have gone through phase one and one for phase two studies and the unlikely possibility that we will have vaccines ready for approval and large scale distribution by the end of the year. It seemed utterly crazy seven months ago, but may well be a real possibility. I would say not to dismiss those that are not in the first run. All of those we’ve discussed, as far as I’m aware, require two shots. That is a huge burden on the health system in developing countries. Getting people back a month later to get a second shot is really challenging. Even in the US that’s very challenging to do. There are vaccines that are in the works that would require, or designed to require, only one shot, but they will not be in the first cohort that has met the requirements for safety and efficacy. So, we will not finish the vaccine story by January 1. We will really just be starting.

MODERATOR: Dr. Bloom, a quick question. You were saying that some of these vaccines require two shots. Why do you need those two shots? Is the second one to ensure a longer period of protection? Or does that actually make the protection better? Why do you need the two shots?

BARRY BLOOM: Because the first shots don’t work optimally in the vaccines that we’ve discussed. And for example, for the Oxford vaccine, the antibody produced was not very high in about half of the individuals after one shot, but all of them got up there after the second shot. That was also true in the forty five people in the RNA vaccine of Moderna, also to be the case.

MODERATOR: OK, great. Thank you, Dr. Bloom.

BARRY BLOOM: If I could just say, we don’t have any idea how long the antibodies, if they’re the key element of any of these vaccines, last because the time hasn’t been long enough to follow how long and effective they are, if they are effective.

This concludes the July 20th press conference.