Coronavirus (COVID-19): Press Conference with Marc Lipsitch, 08/13/20

You’re listening to a press conference from the Harvard T.H. Chan School of Public Health with Marc Lipsitch, professor of epidemiology and director of the Center for Communicable Disease Dynamics. This call was recorded at 12:00 p.m. Eastern Time on Thursday, August 13th. 


MARC LIPSITCH: Thanks, everyone, for joining. It’s been a while since I’ve been here, so it’s nice to see some familiar names and faces and some new ones. I think there are a lot of different things we can talk about and I’m happy to address whatever people want to discuss, if I can. But I think some issues that are very much at the front of my mind right now are certainly vaccines with the news that Russia’s moving forward with the vaccine in the absence of trials, and that a number of vaccines are now in phase three trials. I expect that there will be a quite a bit of debate when data start to come out from those trials, about how much data is enough and whether the data are made public, and the bases for licensing decisions are made transparent or not. 

I think that’s absolutely crucial, especially given how politicized every aspect of this pandemic has become. But in general, for issues as important as vaccine safety and efficacy, a transparent process is really essential. I think it’s not entirely assured, at least in this country. So I’m happy to discuss that further. Then I think the next step as vaccines do become available and the decision shifts from not whether to use them, but how to use them, there are going to be a lot of unanswered questions that are going to make that choice hard. In particular, children are not in the trials, as far as I’m aware of any of the vaccines right now. I might be wrong, but I think they’re all with people over 18. So we will not have an immediate read on their effectiveness or safety in children, which would be one of the typical groups who would be vaccinated for many respiratory infections. As you know, children are perhaps less important for transmission in this infection, certainly, than they are in flu and some other respiratory infections. And that’s another area I’m happy to talk about the conflicting evidence about, because it’s very confusing. But I think we’ll be uncertain about children. 

We may or may not have really good evidence about how well the vaccine works in those populations who are at highest risk if they get infected, such as older adults and those with comorbidities. The decision of whether to prioritize those at great risk of complications where those who are the major transmitters depends a little bit, at least on how well we think it’s going to work in each of those populations. And then the last thing that I think there’s going to be some information from trials, but not complete information from trials about, is how well the vaccine does indeed prevent people from getting infected and transmitting as opposed to preventing them from getting sick if they do get infected. So I think one of the key issues in the design of these trials is to try to maximize that amount, that information, because it’s all very important to try to decide who should get the vaccine when there are limited supplies. 

Then also, the final thing on vaccines is the issue of vaccine nationalism, which people have been pointing to, and I think has not gotten enough attention. There was a nice piece in Bloomberg this week, I think this morning or recently, and there has been some previous attention to that. But I think the issue of how the international community distributes the vaccines among countries is potentially really a big story in terms of the stress on the already stressed diplomatic relations between many countries and particularly between high income countries and low and middle income countries. So that’s not really my area of expertise except that as a global health problem, it is. We want to maximize the benefit of those vaccines, which is a different goal from the goal, perhaps, of some individual countries. I know you don’t come to me for cheerfulness. Those are some of the things that are keeping me up at night. And I’m happy to take questions. 

MODERATOR: Thank you, Dr. Lipsitch. First question. 

Q: Hey, thanks for taking my question, Dr. Lipsitch, thanks for making the time. So this question has to do with Miami specifically. Here we had a pretty startling rise in hospitalizations that started to level off a couple weeks ago. One of the questions we’re asking people is, what might have caused that? There’s a certain degree of population immunity here, I think the models kind of estimate that between 15 and as high as 30 percent. The interventions we’ve had been moderate, you know, they closed indoor dining, there were 10 p.m. curfews, but there was no stay at home order or anything like that. So I guess I just wanted your thoughts on two things. You know, Youyang Gu’s model has the total infected here in Miami-Dade County at 30 percent. But I’m just wondering if that’s a reasonable estimate or if it’s lower, and at what point might you expect that kind of population immunity to slow hospitalizations. 

MARC LIPSITCH: Thanks. So I think I won’t try to evaluate the estimates from Miami because I don’t know the data on Miami in enough detail to have a highly educated opinion. But on the more general question, rather, of how population level immunity can slow transmission, I think there’s been a lot of back and forth in the scientific community and in the news about this, on the issue of how much herd immunity is enough herd immunity. I think a few things are worth really clarifying because that discussion has been confusing even to those of us who do this for a living. So the first thing to clarify is that there are at least three things that are affecting the growth rate or decline rate of the epidemic. The first is control measures, which, as you described, are in place, but not very intense in Miami. The second is seasonal variation in terms of the suitability of environmental conditions for transmission. And the third is population level immunity. And I should say control measures are not just what the government says to do, but what people actually do, and that can go both ways if people do more than they’re asked to do or do less than they’re asked to do. I think we have examples of both of those. So I think each of those is making a contribution to the trajectory in Miami and elsewhere. 

Saying that there is some contribution of herd immunity to bringing the growth rate down or even into negative territory, is not the same as saying herd immunity alone would be enough to get us out of this pandemic at the current levels. So if it’s 30 percent or even if it’s 20 or 15 percent, that, to a first approximation, brings the number of cases each person infects down by 15 or 20 or 30 percent. And that alone is not enough to bring a basic reproduction number of three or four or whatever it was at the outset, down to one or less, which is what you need to get to decline the epidemic. But with control measures in place, the average case is not infecting three, they’re probably infecting two, or one and a half. It depends on the degree of control measures and the place and the time. But what’s important to understand is these things all add up. So a little bit of help from herd immunity, or even a moderate amount of help from herd immunity, combined with partially effective control measures, combined with the fact that it’s summer, which probably is helping to reduce transmission somewhat. Although none of those three things by themselves would get you decline in case numbers, it’s perfectly reasonable. And in fact, my view of what’s happening in many of these places, the combined forces of herd immunity, partial interventions, and seasonal factors, are responsible for the declines in terms of the interventions piece. 

I also have a belief, and I think this will be tested more as we watch around the country, that people have a very local, at best statewide, but often even more local reaction to this pandemic, meaning we watched it happen in Wuhan and we said, well, it won’t be like that here. And then we watched it happen in Iran and in Italy and we said, well, it won’t be like that here. Many people said that or felt that way. Then it happened to New York and New Jersey and Connecticut got scared and it happened in Massachusetts, and all of the Northeast from states were affected. But still, many other states weren’t feeling it yet and and didn’t react strongly. But when a community is really hard hit, as Miami and some others in Florida were have been, I do think it focuses the mind and leads to people taking the control measures more seriously, even if the law doesn’t change. And I don’t have special knowledge of Miami, so I may not be telling a completely correct story about Miami, but I think that has been my observation of the pattern around the country. 

Then the last thing to say on that topic is, one of those things is really in our control, which is control measures and our compliance with the control measures. That, even in Massachusetts has been a challenge, even though we’re at a much better place than in Florida. There are parts of the state where people really aren’t taking the control measures seriously. And where we have significant numbers of cases, on the whole, we’ve done very well, but it’s patchy still. So one thing is in our control, which is how much we use distance ourselves. Another thing is totally out of our control, which is the seasons. And that is likely to get worse, modestly worse, I think, because we still don’t know exactly the magnitude of seasonality. And the third is herd immunity, which to the extent that it is protective and to the extent that it persists, is likely to become more of an aide to our control measure. So, different trends are moving in different directions. 

MODERATOR: Do you have a follow up? 

Q: Yeah, just quickly, and that was a fascinating response, I really appreciate it. This might be a dumb question, but your point on seasonality, you know, here in Florida, we really had our surge in July. Could you help me unpack that? If the seasonality is actually helping, why our huge resurgence happened in July? 

MARC LIPSITCH: Yeah, as I said, nobody that I know of thinks seasonality alone is enough to bring the reproduction number from whatever it is without control measures, down below one, which is what’s necessary to keep a surge from happening. So that really was my point. No one of these forces alone is capable of preventing growing cases which look like a surge if they go for long enough. But the three together, I think maybe. And one of the debates that I think really is unresolved right now is what does seasonality mean for places with a lot of air conditioning, which Florida certainly has. Empirically, if you look at the estimates for flu transmission in Florida, they are quite seasonal and they’re in fact seasonal everywhere. They’re more seasonal in places with bigger temperature swings and humidity swings. But Florida has them, too. So but this is a different virus, and we just don’t fully understand the seasonality of this virus and what causes it. So that’s something that we’re working on, and other groups are working on. But I think our answers are going to be tentative for a while. 

Q: Thank you. Thank you so much. 

MODERATOR: Next question. 

Q: I’m just trying to understand you’re who you think should be prioritized when a COVID vaccine becomes available in limited numbers? 

MARC LIPSITCH: So this is something that we’re working on with colleagues in Colorado and University of Chicago and Harvard Chan, led by Dan Larremore, who is a faculty member at Colorado, used to be in our center as a postdoc. And this is something we’ve been examining carefully. But there is no simple answer. It depends on what your goal is and on the characteristics of the vaccine. So in brief, if you have a vaccine in large enough quantities, meaning enough to cover several tens of percent of the population, then the best way to reduce the number of cases is to vaccinate the groups that are responsible for transmission, which in this case, appears to be young adults and maybe older adolescents. 

In flu, it’s usually younger kids. But that’s doesn’t seem to be the case for this. And that assumes that the vaccine is, in fact, one that can create herd immunity, one that can stop people from getting infected or stop them from transmitting if they are infected. Either or both of those effects would be necessary for a vaccine to work by blocking transmission. If your goal is to reduce deaths or severe outcomes, especially if you have a small number of doses so that getting to herd immunity with the vaccine is not in the short term possible, then with small numbers of doses and to try to reduce the mortality impact, it turns out to be much more advantageous to vaccinate those at highest risk of mortality. With the small amounts of vaccine, you don’t have enough to build up herd immunity and block transmission. And with such a huge difference between, say, 70 year olds and 40 year olds in their risk of dying from this infection or especially 80 year olds and 40 year olds. The vaccine, actually, if it does anything to that high rate of mortality in the older age groups, it’s almost certain to be better than trying to vaccinate younger groups, even if it’s somewhat less effective in those older age groups. So the modeling work that we’re doing is to figure out exactly where the tipping points are. All of this should be publicly available from my talk on Friday at the National Academy of Sciences and Medicine. 

But the question is, what is the tipping point? How much vaccine would you have to have to make the transmission blocking effect method more appropriate or more effective? How bad would it have to be in the elderly compared to younger people to make it not worth vaccinating them, if you’re trying to protect them, but rather more worthwhile to vaccinate younger people and protect them indirectly. So those are all the modeling questions that we’re working on right now. But the the general point is, the vaccine that works on transmission in large quantities is most effectively deployed against the transmitters, and a vaccine that doesn’t work so well on transmission, or that is present only in very small quantities, is most effectively deployed against the by giving it to the people who are at highest risk, assuming that it works to some degree in those people. So that’s a lot of ifs, I realize. But that’s kind of what it boils down to. And that’s why I said at the beginning, that these issues of who it works in and how, are really crucial to get out of the trials. 

Q: On a totally different point, asking for a colleague, in terms of mask wearing, it seems like there’s some data showing that when mask wearing is widespread, people are still getting infected, but less likely to die or to have very serious infection. Are you are you seeing that? 

MARC LIPSITCH: I’ve heard people talking about that. David Rubin at UPenn has been talking about that. I haven’t seen any data from COVID that say that, but I might have missed something. Are you referring to a specific study? 

Q: No. I was referring to a conversation I had with a scientists who is studying that data. 

MARC LIPSITCH: I see. Yeah, I mean, it’s biologically plausible. That does seem to be true for some other infections. But I have not yet seen evidence of that. I think the evidence on masks is compelling, even just for infection risk, even though it’s still pretty limited. But multiple anecdotes and some studies, I think, are pretty compelling together. But in terms of the severity issue, I don’t know the answer to that. 

Q: Thank you. 

MODERATOR: Next question. 

Q: Great, thanks for taking my question. I just wanted to ask a little bit more about vaccines and what you sort of expect as they become available. Hopefully, if they become available in particular, what kind of vaccine do you think is likely? Whether it will be able to stop transmission or just protect against disease? And what are the major challenges that you see in terms of rolling one out? 

MARC LIPSITCH: I think that whether it will protect against transmission is really open. And I don’t know how to speculate sensibly on it. On one hand, the animal trials for at least some of the vaccines, the Oxford vaccine, and I believe one of the others, but I don’t want to say the wrong one because I think it’s hard to keep all of these data straight. But I think at least two of the vaccines suggested a much bigger impact on symptoms and on viral replication in the lungs, but not so much on replication in the nose, which would indicate that they might not be that good against transmission. 

On the other hand, the way you do an animal study, and this I think has been under-appreciated, but the way you do an animal study of a vaccine is to give a dose that is enough to infect most of the animals in your study. Otherwise, you waste a lot of animals who don’t get infected and can’t give you any data. And so you pick a dose, a challenge dose, the amount of virus you administer, to be high enough so that you get good take in the in the control group and hopefully protection in the estimated group. Sometimes, large doses can sort of overwhelm an immune response that might prevent infection or shedding. If the person or the animal received a natural dose, it might not be as effective against a larger dose. Before COVID was a thing, we did a review article looking at this because there was some interesting theoretical reasons to expect that to be the case, that vaccines are not as protective when you get a large dose. There isn’t a lot of animal evidence for any vaccine, but we collected everything we could find and it was all consistent with that notion that it’s possible to overwhelm a vaccine in an animal by just giving it such a high dose. So all that is to say, I think the animal studies shouldn’t be over interpreted and maybe people, even if the biology is the same, might be more protected because it’s the typical dose is not one that infects almost everybody who gets it. 

Q: OK, great. I guess did you have particular concerns about the roll out? 

MARC LIPSITCH: Yeah, I mean, I think I have a lot of concerns. I think the issue of vaccine hesitancy is very concerning, especially among those groups who have been mostly impacted by this virus. Somebody, I can’t remember who, said you should be hesitant about a vaccine that’s unproven. And I agree with that. You know, I do not think that people should be rushing out to demand vaccines that have not been tested adequately. I think getting proper testing for safety and efficacy is really crucial. So I think in that sense, in some some way it’s good that people are unsure how well these vaccines work, because that is the scientific fact. We do not know how well these vaccines work. If that skepticism persists, once the trials have shown safety and efficacy, that will be a problem and especially a problem if it’s politicized and if it’s particularly in most of the groups that have been most affected by this pandemic. So to me, trying to address that upfront while also insisting that we don’t just roll out a vaccine without very good evidence is going to be the biggest challenge. 

Q: And you mentioned earlier there might be a point where, initial data is coming out of the phase three trial, and I guess at what point would you feel comfortable? Do you need it to complete? Or what do you think the FDA is going to do, I guess in terms of getting all the information? They’re going to be getting some information along the way, and I guess I don’t know how they’re going to do it before it’s complete? 

MARC LIPSITCH: Yeah, I wouldn’t want to make any predictions about what will happen in this environment. But what should happen, is that the FDA should apply the same standards that would apply to other vaccines and insist that the data be statistically compelling about safety and efficacy. I think saying that the trial must be complete is a little bit complicated because trials are designed based on assumptions about how much disease there might be in the population. And at least in many parts of the United States, I think we’re outperforming those expectations in a very bad way for public health, but a good way for the vaccine trials. So we might have data earlier than the planned end date, so some of the criteria for ending the trials may not have been met, but we may still have good data. 

I think we have to be flexible about this in the sense of not insisting on things for formal reasons rather than scientific reasons. But we should be not flexible about insisting on good scientific evidence. And because each trial is different, I don’t want to sort of get into the weeds about exactly what good scientific evidence is. But I think the key thing is for it to be transparent enough so that it’s not just what I think, but that there’s a real consensus among the people who are evaluating it without conflicts that the vaccine either is or isn’t safe and effective. 

Q: Thank you so much. 

MODERATOR: Next question. 

Q: Hi, thanks. I’m dying to ask about your hate mail, but instead an offbeat question. I think you saw the question, but I’ll repeat for the sake of others. You’re aware a lot of people are growing increasingly tired of the conflicting and changing messaging on some of this, and some people are confused by the misinformation. You’ve been communicating with the public from the very beginning. What would you most like all Americans to know right now? 

MARC LIPSITCH: That’s a great question. A few things, so I will prioritize. I think the first thing is just the very fundamental notion that if you have susceptible people and you have human contact and you have a virus to which those people are susceptible, it will spread. The number of cases will increase. My friend Bill Hanage sometimes says viruses don’t read Twitter. They don’t care what we think about them. They don’t care what they do to the economy. They don’t care about anything like that. And we have to be rational in the knowledge of that, that if a certain level of control measures, for example, didn’t bring transmission under control in the summer, unless there’s a lot more herd immunity to help us along, those same control measures still aren’t going to bring transmission under control in the fall and winter. Conversely, as more people start to get together in various ways and as schools reopen, there will be more opportunities for transmission. And wishful thinking just doesn’t help. I think that’s been a big part of the issue is is a notion in some states in particular, that somehow we can be different from all the other experiences with this virus and other viruses, and that we can just hope that it won’t spread when we have high levels of contact. 

In the more particular categories, I think it would be great if people understood that masks, although they’re somewhat disgusting to wear all day or even for an hour and a half, really are a part of the solution, both as a direct protective for yourself and especially others, but also as a reminder for people, because they see the mask, they tend to stay away. I wish there was a bit more sense of national solidarity in the idea that if the virus is spreading, fast and at high levels in a community, it’s destructive to the economy, it’s destructive to every other aspect of people’s lives, and the need to get the virus under control is, in fact, an investment in the economy and in getting our lives back it to a normal state, rather than the sort of opposition between the opener’s and the closer’s. I think of all of us closer’s, if I can use that term, want to close so that we can get things under control enough so that we can open. Nobody likes closed. 

Q: Thank you for that. And my follow, if you don’t want to go into it, I would understand. But I’m curious if you think scientists and health care experts and journalists have all maybe talked and written about all this a little bit too much?

MARC LIPSITCH: I mean, it depends what you mean too much. I’m really bored of reading about COVID. 

Q: And that’s exactly why I ask the question. I think a lot of people are tuning out because every day there’s an incremental new finding or argument on this, that and the other. 

MARC LIPSITCH: And you may mention also of the contradictory aspects. I think it’s a little hard to know what people who don’t do this for a living, how you live in a news and information world that’s so COVID centric. For me, it’s one experience. But for people who actually care more about other things, it’s a presumably quite different experience. But I don’t know. I mean, it is dominating every aspect of life because it’s changed our economies. It’s changed our educational system. It’s changed our sports. It’s changed our other forms of entertainment and arts. I mean, it really is the story. And I don’t know what to do to stop it being dominant other than stopping the virus itself. 

My overall evaluation of the coverage of this is that it’s been surprisingly good compared to, you know, speaking really generalizing across different media types, but almost every reporter I’ve had contact with has been trying really hard to get the story right, to understand uncertainty and to communicate clearly what’s what’s known and what’s not known. And I wonder almost if this is kind of a reaction to the fact that there hasn’t been a clear government voice in the United States that’s been loud enough at the federal level, or able to speak enough at the federal level to fill that role, which is typically the CDC’s role. So I think journalists and scientists are collaborating quite effectively, in my opinion, to bring that kind of information out with all the nuances. But, of course, it’s you know, not that many people want the entire newspaper to be science or medicine or even public health, you know, we all look forward to it being less relevant. 

Q: Compelling thoughts. Thank you so much for that. 

MODERATOR: Next question. 

Q: Doctor, nice to virtually meet you. Thank you for taking the time to do this. My question is about Dr. Robert Redfield, the director of Center of Disease Control. He said that we are predicted to have the worst fall ever, if people start taking this more seriously. It’s not just because of the cold and flu season converging, the CDC believes we did not do enough to mitigate COVID. So what can we do now to make sure that we don’t have the worst fall ever? 

MARC LIPSITCH: That’s the many billion dollar question. I think the answer is for what’s left of the summer, any place that is in the sort of yellow and orange and red zone and the Harvard Global Health Institute’s map, or has more than more than, say, 10 cases per hundred thousand per day, needs to intensify its control measures. And sometimes it’s clear what that means because some places are still having a large number of indoor activities that transmit. Some places like Massachusetts, which is not in those ranges, but is at a lower level of transmission, there are still pockets of transmission and pockets of people anecdotally and from data, who are just not complying with mask requirements and having large gatherings despite the limitations and the like. So I mean, I think it’s a real combination of individual actions and government actions in the places where there are still some significant actions to take. 

The other thing I think is, we have to get testing more available and faster. The good news, I got a COVID test yesterday, because we’re traveling, and I got my results in 18 hours, which astonished me. And that was at a community health center and in Jamaica Plain where I live. It was easy to do, it was a two hour wait in line in the sun, but once it was done, it was 18 hours to result. It is possible to do that. But still around the country, there is a huge delay in testing, which means that people don’t know that they’re infected until long after they’re probably no longer contagious or no longer very contagious, if they were infected. And conversely, if they were not infected, they don’t find out that they’re uninfected for a long time and then can’t plan accordingly. So I think speeding up testing, and as my colleague Michael Mina has pointed out multiple times, I think also on these calls, having tests that individuals can do privately and that are point of care so they get the answer immediately, would be a huge improvement and would also make it possible to do larger scale screening in schools and in other congregate settings. There’s a huge regulatory hurdle to doing that right now, and he and others are trying to solve that. But it’s not a technical problem. It’s a regulatory problem at the moment. So those are some of the things. 

Q: You briefly just mentioned school. I’m down here in Florida. Do you believe that President Trump and our governor, Governor DeSantis and others are not taking going back to school seriously enough? What’s a parent to do? What’s a teacher to do? 

MARC LIPSITCH: Yeah, it’s a very, very hard question. My colleagues and I wrote a commentary in the New England Journal of Medicine two weeks ago arguing that primary schools, elementary schools, should be reopened in places that have reasonable degree of control, which is significant part of the country, but not Florida, for example. High schools are much harder and places that are in high transmission periods are also much harder. I think the Cherokee County example near Atlanta shows that reopening schools in the midst of significant community transmission can turn them into amplifiers. And you know, my only advice in places that have really high levels of transmission right now, is that you’ve got to just decide whether you care more about your bars or your schools. And if the bars are closed, what else can you? What else can you do to stop transmission? It’s not impossible to do. Much of the country has done it much. Most of the world has done it, or big parts of the world have done it. So my advice would be get your priorities straight. And that may mean you don’t have school for a while because you’re getting it down. But that’s a legacy of not having priorities straight a few months ago. 

Q: You may have already been asked this, but I just thought it was fascinating about mixed messages that people are getting. You know, we’re seeing a lot of public health versus personal choice debate. Is there anything that we can do to get more people to choose public health over personal choice? 

MARC LIPSITCH: That’s a great question. I am not an expert in how to promote prosocial behavior. But, you know, this is a threat to everybody. And if for the 20 year olds who are likely to do just fine if they get infected, they all have relatives and friends who are not 20 and healthy. And I think continuing to to make that a theme is the best we can do. But there are other people who are smarter than I am about how to move public opinion. 

Q: Thank you. That’s it for me. 

MODERATOR: Next question. 

Q: Hi. So I am a children’s reporter and I’m reporting on K-12 education. So we’ve had surrounding school districts already open up and see COVID-19 cases. I have two questions for you. Is the number of COVID cases in a school a good indicator of COVID risk for other students? And second, how should schools and districts communicate these positive cases? 

MARC LIPSITCH: I think this is something we’re gonna have to learn over the next month or two. Clearly, the more people are infected in a school, in truth, which is different from how many we know about. But the number of truly infected people in a school determines the level of risk of transmission within the school because each case is a potential source. The fact that you have multiple people in a school infected does not, though, mean that those people got infected in the school. Other countries that have had schools open at other times of the year have faced challenges in trying to determine whether clusters of cases are really transmission’s or are just reflecting ongoing community transmission. So I think that each state and district is trying to work through these issues at the same time. I don’t know what the right way to communicate cases is, I think that openness is clearly important. Privacy is clearly important of the individual people, although those people, once identified, should not be in school themselves. 

It’s going to require good investigation and this is something we’ve been pushing for at the state level in our own state, my colleagues and I, is to have really good investigations happen in the schools that do experience multiple cases, to figure out if there’s transmission, and especially why there’s transmission. The data are pretty good for elementary school students, that they’re less likely to get infected and perhaps less likely to transmit than older kids and adults. So if there is a lot of transmission, as there was in the summer camp in Georgia, or in some other settings with young kids, distancing practice is probably not being done adequately. And so if we can understand, of all the places that might have outbreaks, which ones do and what they’re doing or not doing, it can help us to improve practices everywhere else, and learn from the mistakes. It’s never easy to use other examples to learn from because nobody likes to be the example. And sometimes it’s hard to investigate, for that reason. But that should be the spirit within districts and across the country. 

Q: Awesome. Thank you. 

MODERATOR: Next question. 

Q: All right. Thank you so much for taking my question. So my question is more about kind of the technologies being used in the new COVID-19 vaccine candidates and development. MRNA vaccines such as the Moderna candidate, are fairly new. I mean, correct me if I’m wrong, but I don’t think there’s any such vaccines currently on the market. And then also the adeno-5 vector used in the one of the Russian vaccines and the CanSino vaccine candidate, has a really poor history in HIV vaccine development. So I was wondering if you could talk a little bit more about these different underlying technologies used in the different vaccine candidates, what researchers are concerned about, and what they’re kind of looking for? Thank you. 

MARC LIPSITCH: I don’t know if Barry Bloom is still on the call and would like to take that question? 

MODERATOR: Yes, he is very. 

MARC LIPSITCH: Barry, can I put that to you? The question was about the technologies and the fact that MRNA has never been used as a vaccine and they adeno-5 vector sometimes doesn’t have a great history. And what should we think about in terms of all these new technologies for vaccines? 

BARRY BLOOM: So just to take the first two points, I’m impressed, actually, with the confidence that the NIH has in the RNA vaccines. And I wonder what they know that I don’t know, because it has been used, and in several hundreds of people prior to COVID-19, for two strains of influenza and either MERS or Ebola. So these so-called new new vaccines have actually run through phase one trials in humans. And I think people were confident they knew something about what the short term adverse effects might be. There is, in fact, an approved licensed adenovirus vaccine for adenovirus, that I only found out about recently, which is only available to the United States military, and there’s a lot of use in that vaccine with relatively low numbers of serious adverse effects. So, again, adenovirus is not quite startling, the Oxford Group had tested it in MERS and it Ebola, I think. So we’re not starting from just square zero. 

The issue with phase three trials and why the Russian announcement is so distressing, is what you really want to know is uncommon or relatively rare adverse effects, particularly if people become reinfected after vaccines, and when vaccine antibodies, for example, wane, is that a scenario for enhancement that you wouldn’t see in a phase one or phase two trial? And there is no shortcut to that. Every sign that we’ve been given from FDA going on webinars with the editor of the New England Journal of Medicine, to say the NIH and the FDA are not going to allow shortcuts. The Russians have surely taken a shortcut. They’ve probably had a lot of use of that vaccine for other things. But every batch of vaccine in the US is characterized for its adverse effects. So if a kid gets sick from a childhood vaccine, they can dig out the batch number of that vaccine from that company, and track down whether anybody else got sick. You can’t do that if you haven’t done a detailed phase three study on all of that. 

So I just think the serious issue on vaccines right now that I’d be curious if any of the reporters know, how do you volunteer? How many people have volunteered? How do you get 120,000 people to volunteer for four vaccines, each of which requires apparently 30,000 people? There is a notice up at NIH on the website. You can volunteer or you can apply to volunteer. But there are criteria that you have to provide information, and they want people over 60, to my knowledge, I don’t know if they include children, I do know they do not include pregnant women for the current plan. So we haven’t heard a lot about how to sign up a lot of people for vaccines. And the question is, are there enough people to test them? And are they all being tested in the U.S. or elsewhere? 

MARC LIPSITCH: I got solicited for the Moderna trial yesterday when I was in line to get my COVID test. 

MODERATOR: Dr. Bloom, I have a note here that as of July 20th, Fauci said 138,000 people have signed up for the NIH volunteer system, but we don’t know if it’s diverse enough. 

BARRY BLOOM: It’s actually, I think, a little higher than that on the NIH website, but that’s not 120,000 people. 

MODERATOR: Did you have a follow up or are you all set? 

Q: Yeah, actually, I did have a follow up. Thank you for that comprehensive answer. You mentioned that vaccine development is just moving so fast in this case. And you mentioned that we really don’t know the effects of a potential vaccine on reinfection or things like that. So I was wondering, as an expert working in this field for a long time, how long do you think we have to wait to kind of learn these things? Because, you know, in the case of the Dengue vaccine, that didn’t happen until after it was approved.  

BARRY BLOOM: Marc, you want to comment? 

MARC LIPSITCH: I’m sorry, I didn’t understand the question. How long do we have to wait to find out about enhancement? 

BARRY BLOOM: The adverse effects.

MARC LIPSITCH: Yeah, I don’t know the answer to that either. 

BARRY BLOOM: Maybe I would just make the following comment, which everybody talks about phase one, two and three trials. There is a phase four called post licensure surveillance. And in the guidelines that were put out by FDA, it is not very specific how long that surveillance should be. In my view, anything less than two years would be a grave mistake. And that’s a big deal, following up all the people who are volunteering, but are going to go for 10 visits and samples to see how they make antibodies. But then after six months, will they be tracked down long enough to pick up the kind of adverse effects that one wants to know about? But there has to be post licensure surveillance. 

Q: OK. Thank you very much. I think that’s it for me. 

MODERATOR: Great. Thank you. Next question. 

Q: Yeah. Thank you so much, for taking the question. We’ve been covering warp speed a lot, and all the different contracts for therapeutics and vaccines. And clearly, what U.S. is trying to do, is buy up a lot of the first access to vaccines, also to therapeutics with Remdesivir and at least for Regeneron, they bought pretty much the entire stock the rest of the year. Should that be authorized? And so I’m curious, you mentioned vaccine nationals’ at the top of this, but I’m curious sort of from a public health perspective, from a U.S and from a global health perspective, how do you think about the tradeoffs of that or the negative consequences of the U.S. trying to get a significant portion of what’s available in terms of treatments and vaccines of COVID-19? 

MARC LIPSITCH: Well, I mean, I think there are certain global resources that are scarce. And when one country tries to monopolize them, that’s seen as aggressive by other countries. And when they are life-saving resources, that’s seen as particularly aggressive. And it’s not that surprising everybody wants them, but being a global outlier area in the level of aggressive tests will lead to other countries changing their opinion in a negative way of the U.S.. It’s not my field diplomacy, but as my family is well aware. But, you know, just sort of reasoning about it, I think it will be seen as aggressive in proportion to how much we do or don’t try to expand the supply and make it available to others at the same time that we’re trying to help ourselves. Another approach, rather than just saying let’s grab the limited supply, is instead to figure out ways, multilaterally, to expand the supply, which is what a sort of good member of the international community would do. 

Q: Just one follow up in a very different note. As far as distribution goes, where should prison fall on that list? 

MARC LIPSITCH: That’s another great question. So prisons have been the sites of major outbreaks and clearly transmission in prisons is intense. So in that sense, there’s a strong case for prioritizing prisons as sites of intense transmission, especially for a vaccine that works against transmission. On the other hand, if there was a vaccine like that that was really good against infection and transmission, it would be hard to generate support for prioritizing, say, prisons over health care workers. Who, also themselves, but especially for their patients sake, benefit from not being vectors of transmission. So I think there’s a case to be made. But prisoners have not traditionally been at the top of our priority list for much of anything in this country. So as a matter of fact, I don’t really expect to see them prioritize very highly. 

Q: Thank you so much. I appreciate it. 

MODERATOR: Do you have any final thoughts before we go, Dr. Lipsitch? 

MARC LIPSITCH: No, it’s been an interesting discussion. Thanks for great questions. 

This concludes the August 13th press conference.