Coronavirus (COVID-19): Press Conference with Stephen Kissler, 12/30/20

You’re listening to a press conference from the Harvard School of Public Health with Stephen Kissler, research fellow in the Department of Immunology and Infectious Diseases. This call was recorded at 11 a.m. Eastern Time on Wednesday, December 30th.


MODERATOR: All right, Dr. Kissler, do you have any opening remarks?

STEPHEN KISSLER: Nothing other than it’s good to see you all. And happy almost end of 2020. And thanks for all the work you’ve done over the course of this year to help make the science and the epidemiology more accessible. I think it’s played a really important role. So that’s all I wanted to say before we start.

MODERATOR: And thank you, too, Dr. Kissler. You’ve been a huge part of that as well. All right. First question.

Q: Well, thank you for taking my question, and I know this is basic and we’ve said it many times already, but vaccinations have started rolling out to the public here in my community in Florida. And so we’re hearing a lot of chatter from the seniors who are getting it about how they’re excited they can now hug their family members. So could you explain why one dose is not full protection and the precautions they should still be following while they’re waiting for their second dose?

STEPHEN KISSLER: Yeah, so there are a couple of important considerations there. The first one is time. It takes a little while even for that first dose to kick in. It does seem like the first dose gives some amount of immunity to the coronavirus, but it won’t get you up to that ninety-five percent of efficacy that we’ve observed. So even after you’ve gotten the vaccine, it takes on the order of a week or two before your body can mount that immune response that makes it a little bit safer to see others. And then, of course, with one dose and even two, the efficacy of the vaccine is not perfect. And the statistics that we have for its efficacy are averages across age groups. Now, there’s good evidence that the vaccine works very well in older people as well, but even so, I think given the heightened risk that comes with a coronavirus infection with older, I think there’s still very good reason to keep bearing in mind some of the same physical distancing strategies that we’ve had in place up until this point. You know, the vaccine is one more tool in our toolbox, but it’s not a perfect protection, especially after just one dose. And so I think that it’s still a pretty good measure of caution is warranted.

Q: Thank you and I have another question, but it’s unrelated, it’s something that we’ve been asked a lot by viewers. If you do have the coronavirus right now, if it’s in your system, when can you get the vaccine?

STEPHEN KISSLER: Yeah, so at the moment, and to my knowledge, there’s no requirement that a person who’s been previously infected with Coronavirus is barred from getting the vaccine in any way. And in fact, it’s encouraged that people who have a previous infection to get the vaccine as well. Now, I would I think that this is probably a question that as with anything that involves your own individual decisions with respect to your health care, should be directed towards your personal doctor if you had a very recent coronavirus infection and you’re also eligible to get the vaccine. That’s something that should be worked out and weighed with the particular risks and benefits in your particular situation with your doctor. And I think it’s not really something that we can speak to from that and give sort of overall guidance. So that would be my suggestion is to just go with the doctor who knows your situation and they’ll be able to advise, depending on how recent your infection was.

Q: OK, but if you actively have it, like right now, if I’m testing positive, I don’t qualify for the vaccine?

STEPHEN KISSLER: I actually don’t think I can answer that question. I’m not sure about the particulars of that.

Q: Fair enough. Thank you very much.


MODERATOR: Next question.

Q: Hey, thanks, Nicole. Thanks, Dr. Kissler, for taking the question. Here in Florida, we’ve had a pretty, I would say, chaotic rollout of the vaccine. We had five hospitals receive about 20,000 doses, and they were given very wide latitude about how to administer those doses. And what we’ve seen is that nonmedical workers in these hospitals have gotten these vaccinations. And I’ve got tons of tips in my email inbox and my voice mail of people who work from home, people who are younger, people who really don’t fall under those federal guidelines. Now we’re pivoting towards seniors and the hospitals are really being given the bulk of the responsibility in getting these doses out there. I just was curious for your kind of big picture view on how this has been handled here in Florida. Specifically, it seems like the move to pivot toward seniors was almost prompted by what the hospitals were doing with the doses they received. And it just seems like there’s a total lack of coordination going on right now between the federal government and the state, the state government and the localities as far as how to prioritize this vaccine. So I was just curious to get your perspective on why this might be a challenge and what the ramifications of this kind of sloppy rollout are going to be going forward.

STEPHEN KISSLER: Yeah, so to give a little bit of credit where credit’s due, vaccine rollout is always an incredibly complex and difficult process and so in good faith, I do imagine that the people who are working on this are doing the best that they’re able. But I think there are a couple of factors in play here. One of them simply, I think, is that many of us, we’re now coming to the end of 2020, and we have a vaccine, which is sort of fast. It’s about as fast as any of us could have hoped it could have come about. So that shortens a little bit of the time that we might have had to plan for the vaccine rollout and really streamline the vaccine rollout. So in a way, it’s a good problem to have that we have the vaccine very soon. But of course, I think it caught some of us flatfooted in a way where we’re now in exactly these situations where we have to make these complex decisions about whom to prioritize and when and why and how. And it leads to some of the situations that you’ve been talking about now, based on the work that I’m aware of and some of the work that I’ve been involved in, it really does seem to make a lot of sense to prioritize vaccines to those who are at highest risk of severe complications from the illness. And so that that clearly puts older people high on the list of people who you want to vaccinate first. So I think that it’s good that we’re swiftly moving that direction. I think that. Yeah, it’s hard to, I’m not sure that it’s my role to play in any sort of judgment or evaluation on what’s already happened. But I think that moving quickly in the direction of vaccinating the people at high risk of infection and the people, especially people in congregate living facilities where there’s also a very high risk of infection, is just the best thing we can do. And as quickly as we can do that, that’s what we should be doing.

Q: I mean, the system at the hospitals have set up, Dr. Kissler, is basically, you know, we’re going to put out a hotline and it has people calling nonstop and trying to get an appointment. You know, I have seen commentary from people saying they had their entire family calling to try to get through to schedule an appointment for their abuela. But I would imagine if you’re living alone, if you’re a senior, without that family support, it would be really hard to navigate and to get an appointment on your own. So I guess I’m just wondering what your thoughts are about that mechanism that the hospitals are using where they’re basically just putting out a hotline or they’re putting out a portal and saying, hey, go ahead and sign up. Shouldn’t it be a more proactive effort to get into these communities, especially people where there might not be a lot of health care access to make sure that everyone’s kind of getting a chance to line up for these doses?

STEPHEN KISSLER: Exactly. Yeah, I think the vaccination plan ideally should be as proactive as possible. Again, it’s complicated partly because of just the way that the vaccines need to be stored, that really only a hospital has the sort of facilities right now to store the vaccines at these super cold temperatures that the Pfizer vaccine in particular needs. But that said, the outreach can still be done, I think, in a much more proactive way and should be. You know, there are so many instances, both with COVID-19 and with so many other health issues, where we see these vast disparities in access to care that can lead to these downstream health consequences, which in this case means people who have less access to care, fewer people to advocate for them, will get the vaccine later. And that can really entrench these huge health disparities. So my hope is that the plan would be more proactive. And I hope that those plans are coming into place. But I’m not aware of many of the particulars here. But yes, ideally, we would have a very proactive strategy to get people signed up for the vaccine, at least.

Q: That’s it for me. Thanks so much and have a great New Year and thanks so much for all the all the insight you shared over the last year. It’s been really helpful.

STEPHEN KISSLER: Thank you very much. Happy New Year.

MODERATOR: Next question.

Q: All right, thanks for taking questions. General question, how concerned should we be about the U.K. variant? And a little more specifically, how concerned should we be about the reports that it’s, whatever, 57 percent more transmissible?

STEPHEN KISSLER: Yeah. So there are a few things I’ve really been paying attention to with respect to the U.K. variant and in speaking with some of the scientists over there as well. There’s definitely a high degree of concern about its increased transmissibility, its increased infectiousness. There’s a lot of good evidence that suggests that it is, in fact, more transmissible. Now, what exactly that number is, is kind of hard to tell. But the fact that it’s been able to displace other strains that were previously in high circulation of the UK is definitely a cause for concern. There are practically speaking, there are a few things that this then means. So on the one hand, it means that the virus is a little bit more difficult to keep control of. And so it essentially means that more effort is going to be needed to, in a sense, flatten this curve much like we did earlier in the spring. And if it is in fact more transmissible, which there seems to be good reason to believe that it is, it’s also going to increase the number of people who need to be vaccinated to fully protect the population from the spread of this variant so that imposes two important logistical challenges, just sort of right at the outset. Now, one of the things that I’ve heard a lot of people speaking about is the difference between, there’s this strain that seems to be more transmissible, but it doesn’t seem so far like it necessarily leads to more severe infection. I think the intuitive response to that is to sort of breathe a sigh of relief. But there’s a nice Twitter thread from a couple of days ago by Adam Kucharski, who was talking about sort of weighing these two different threats. And in a way, having a strain that’s more transmissible is in some ways a greater threat, because with something that grows exponentially like this, due to the increased burden of infection that you end up getting, it can actually lead to a greater total number of severe illnesses and deaths than one that would just have a proportionately higher case fatality rate or something like that. So I think this is something we’re going to have to watch closely and put in an awful lot of effort to try to control. And so, yeah, I think that this is going to be a major part of our coming months.

Q: And do you have any thoughts on whether the vaccines will work against the UK variation?

STEPHEN KISSLER: All of the consensus that I’ve seen among the scientific community that I’m aware of seems to say that the vaccine should still be effective. To my knowledge, the trials themselves, really the studies that will actually definitively prove that have not yet been done. But based on the genomic changes that we’ve observed, they don’t seem like they have changed the parts of the virus that the vaccine targets specifically. And so I think there’s very good reason to believe that the vaccine will still be effective against this variant.

Q: And just to jump back to clarify one thing, what we’re saying is if it still has the same severity, but 10 million more people are infected, then the percentage of people among that group who would be seriously ill, the raw number would be larger in the I’m having a little, even if it sounds good, that it’s the same severity, but if the total raw number of people infected is greater than the total number of people severely ill will be larger?

STEPHEN KISSLER: Exactly. Yeah, that’s the idea.

Q: Thank you very much.


MODERATOR: Next question.

Q: Dr. Kissler, thanks for taking our questions today. I’m thinking about unanswered questions, I think there are three that I’m aware of, and these are all vaccine related questions. Whether the vaccines prevent someone from being infected, which would obviously reduce the transmission rate versus just the symptoms, and then also how long immunity lasts. And I’m wondering how we’re going to get the answers to those questions is that I’ve heard that those are research questions. And then what would that require?

STEPHEN KISSLER: Yeah, those are those are very central and burning questions for sure. So I’ll take them independently. The question of whether the vaccine prevents infection, as you say, is a very important one. Our estimates of what it will take to achieve population immunity really rest on the assumption that it does have some amount of ability to block infection or at least to block transmission. So one way to measure that is by following people who have been vaccinated and longitudinally testing them to see whether they actually do become infected or not. That requires, you know, a vast amount of testing, but in theory is something that we should be able to do and I believe will be a part of many of the Phase four trials that are going on with the vaccine right now, where people who get the vaccine will be followed up and tested periodically to see if they’ve been infected and maybe asymptomatically infected. So those efforts are ongoing. And so my answer is an answer that we should be able to have in the not too distant future simply because there’s so much infection going around that the risk of getting infected is very high. So if there is actually an effect, if there is actually a reduction in the risk of getting infected with the vaccine, we should be able to see that pretty soon. And those studies are ongoing. As far as the duration of immunity, that’s a more difficult question because that requires just a much longer span of time following people up. You know, we’re really only beginning to get a sense for what the duration of immunity is from natural infection, even though the virus has been with us for about a year. And so, unfortunately, the only way to really get a clear answer to that question is to spend at least as long following people up as you want to know how long the immunity lasts. There are some ways to sort of begin to get out the question before following people up that long. You can check sort of the level of antibodies in a person’s blood and how they decline over time. But there’s a fallacy that we can run into where if you just draw a line through that curve, basically you see the rate at which antibodies are declining, but it doesn’t just keep on going down consistently. Oftentimes it sort of goes down and then reaches a baseline and sort of levels out at that level. And that’s what gives you sort of this longer-term immunity. So unfortunately, to make a long story short, that last question about the duration of immunity is not something we’re really going to know for quite some time. And, yeah, we’ll just have to keep doing. People are doing the work now because it has to start now if we want to know what the answer is in a year’s time, but we won’t actually know the answer until we’ve actually just seen this play out.

Q: Right, and it seems like since the vaccines themselves are rolling out on a sort of sequential basis, that the Phase four trials are also going to be lagging depending on that time sequence, right?

STEPHEN KISSLER: That’s right. Yeah. So the research in some ways, is constrained by the way, in which the vaccine is rolled out in these phase four trials.

Q: OK, thank you.


MODERATOR: Next question.

Q: OK, can you hear me?


Q: Thanks for taking my questions. First of all, President elect Joe Biden says he wants to give out 100 million doses in his first 100 days as president. What difference will that make to containing the pandemic in the United States? I mean, the number 100 million, what would that mean based on your modeling knowledge expertise?

STEPHEN KISSLER: Yeah, so to reach that level of vaccination that quickly would be great. We’d still be a way away from the level of immunity that we need in the population to completely stop the transmission. But it would go a long way towards reducing it and towards protecting the most vulnerable. So, I mean, if we’re talking about just in the United States, that’s on the order of one in three people, I think. And so that would go a very long way towards preventing the spread of coronavirus. Now, going back to one of the previous questions that was asked, we have the concerns about this novel variant too, which might be potentially more infectious. And if, in fact, it’s true that this novel variant basically has a higher reproduction numbers, spreads more easily, but also that the vaccine is protective against it, then essentially what we’ve entered into is sort of this race where we want to vaccinate as many people as we can, as quickly as possible to prevent this new variant, really being able to take hold in the population. So I think that really vaccinating as many people as we can very quickly is a very good idea. It’s a good idea regardless, but especially in the context of the spread of this novel variant, I think that it could become even more important and potentially save more lives if we can reach that level of protection that quickly.

Q: OK, so what is your number of building population immunity in the United States, like how many people need to be vaccinated?

STEPHEN KISSLER: It’s a very difficult number to come down on because there are so many complexities to do the way that that works. So just to give one example, you can set a threshold, sort of roughly speaking, for how many people need to be vaccinated in any population to prevent the spread of disease. But vaccination isn’t done uniformly, and our interpersonal contacts aren’t uniform either. So we might have very high coverage in one area, but very low coverage in another. And in the place where the vaccine coverage is very low, then infection will still be able to continue to spread. So roughly speaking, if the virus has a reproduction number of about three, so that means an infectious person is likely to infect three others, then that means that you need essentially two thirds of the population to be fully protected. And so you’re going to need somewhat higher than that number to have the vaccine. So that’s where some of these estimates of maybe 70 to 80 percent have been coming from, which is which is quite a large number. You know, that’s on the order of 225 million in the United States. Now, of course, with the more infectious variant, that number may increase even further. And so we’re reaching really high levels of a vaccination that’s required. And simply because of this variation in which communities have higher levels of vaccination, we’re going to have to go even higher than that to make sure that really, the goal is to have even the least vaccinated communities, to still have that high level of population immunity, which requires a really, really large amount of people to be vaccinated. I know I’m speaking in sort of qualitative terms here, but I think that that’s the best I can do.

Q: OK, thanks. One more question today, UK just approved emergency use of the AstraZeneca and Oxford vaccine, and we know that this vaccine takes newer conditions for logistics. So once this vaccine is approved globally, what difference will that make to the pandemic, to the containing?

STEPHEN KISSLER: Yeah, so the two great benefits that I see for this vaccine is that it’s as you said, it’s easier to store and as a result of that and other elements of its production, it’s cheaper. So basically, those two things simply mean that it’s going to be a lot easier to distribute and especially to distribute to communities that don’t have the infrastructure to refrigerate vaccines and communities will be able to basically buy more doses with the same amount of money as well. So from my perspective, it’s very good news that this has achieved the authorization, because it really does mean that we’ll have doses going to places that might not get them otherwise and we’ll have more doses going everywhere, which will, again, just sort of get us closer to that first goal that we were talking about of vaccinating as many people as quickly as we can. So I think it’s very good news. It’s an important breakthrough and it’s really a different sort of vaccine than the Pfizer and the Moderna vaccines. And it’s just really good to have that variety because no one vaccine is going to be able to do everything. And so having multiple options is going to be immensely helpful, especially from a global perspective.

Q: OK, so over 20 countries have found like infections of the of the Great Britain variance, so can we estimate the real numbers of infections of this new variant based on the discovered cases.

STEPHEN KISSLER: So it’s possible to estimate numbers of cases roughly. I won’t be able to give you an actual number I’d have to direct you to, in particular, Trevor Bedford has done some really good work on this. Again, he’s been very active on Twitter. If you’re able to look through some of his work as well or to contact him or colleagues. So Trevor Bedford and Emma Hodcroft as well, whose been working on it from the European side as well, have both been sort of running these rough estimates, using the genetic variants of this new genetic variants, so variations on that variant to try to estimate the total population size who might be infected with it. So it’s possible I would need to review those numbers to give you an exact number for sure. But people are running those calculations and getting rough estimates for the bounds of the numbers of people who might already be infected with this novel variant. So the fact that it has already been found in so many different countries is, I think, good reason to believe that its circulation is pretty widespread. And so it’s something, again, we’re going to have to watch closely. But I think that it has very quickly become a global issue and something that we’re all going to have to keep track of around the world.

Q: OK, thank you. Did you say Trevor Bedford?

STEPHEN KISSLER: Yes, that’s right.

Q: Yeah, OK, I’ll search him later. Thank you.

STEPHEN KISSLER: Great, thanks.

MODERATOR: I have a link to Adam Kucharski, really quick to put that into the chat. And I can look up Trevor Bedford as well. Dr. Kissler, it looks like that’s our last question for today. I don’t know if anybody else has any other final questions? If so, just raise your hand. And if not, do you have any final thoughts for us?

STEPHEN KISSLER: I think that’s all. Just take good care and hope you all have a happy New Year.

This concludes the December 30th press conference.

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