Coronavirus (COVID-19) Press Conference with Stephen Kissler, 12/07/21

You’re listening to a press conference from the Harvard T.H. Chan 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 Tuesday, December 7th.


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

STEPHEN KISSLER: Yeah, I know that a lot of the big news lately is about the Omicron variant, and we’re still sort of in this frustrating time where a lot of my answers to questions have been, we don’t know yet, and we’re still waiting to see. But hopefully with your specific questions, I’ll be able to give a little bit more insight into what we do know, what we don’t know and maybe how long it’ll be before we have more information.

MODERATOR: Great. Thank you, Dr. Kissler. First question.

Q: Nicole, thank you, want to make sure you can hear me all right?

MODERATOR: Sounds good.

Q: Doctor, thank you for doing this as well. This has been very valuable throughout the pandemic. You mentioned that at this point, it’s a little frustrating because we don’t have the answers, and that’s sort of what I want to address. We see the stock market fly all over the place at the remark of a doctor, Fauci, who says things look encouraging. But and yet yesterday, the city of Boston announced that the positivity rate is at 5.2 percent, which a year ago would have resulted in closing down schools. My first question is where are we in this? What can we say about this pandemic at this point? Are we on the way out? Are we in the midst of a surge or what are we actually looking at as we sit here today?

STEPHEN KISSLER: Great questions, and I would say in some ways, both of those statements are true. So here in Boston, we are in the midst of a surge. Most of that surge, as far as we can tell, is driven by Delta still. So we’ve documented a couple of cases of Omicron in the area. But the surge that we’re currently seeing, which is responsible for that 5.2 percent positivity and for the exceptionally high levels of virus that we’ve been detecting in wastewater, for example, is mainly Delta. We know that SARS-CoV-2 is a seasonal virus, that it’s especially here in temperate regions where it gets colder in the winter. It just gets harder to control in the wintertime, and so I think that’s part of what is behind the surge. We’re probably going to see, we were talking about this last year too, but a surge within a surge whereas the Omicron variant begins to take off, that’s going to add fuel to the fire. And I think it will make the virus more difficult to control over the winter that it would be otherwise. But that said, we have a lot more uptake of vaccines. Even, you know, the news of the Omicron has prompted several people to get vaccinated who haven’t been previously. And even though Omicron does seem to have some potential to get around our immune responses, I do think that vaccination will help a lot. And part of the reason why we have this high positivity rate but maybe aren’t seeing some of the restrictions that we saw last year is in large part due to the vaccines, because the vaccines have reduced the odds of people going to the hospital and dying from COVID-19. So on a case by case basis, thankfully due to vaccination, the virus is less severe. We’re going to have to watch this closely to see if that changes at all with the spread of the Macron variant. But for now, given that we’re mainly dealing with Delta, that’s what we’re dealing with as high cases, but thankfully relatively lower rates of hospitalization and death.

Q: But when experts like yourself and Dr. Fauci say it’s going to be a while before we know for certain how difficult the Omicron variant is going to be to deal with. What’s the process that’s underway now that will eventually give us that answer? And how long will it take? I know we can’t tell people what the answer will be, but can we at least say, well, we think we’ll know by such and such?

STEPHEN KISSLER: Yeah. So the reason the these timelines are in place, why it’s taking us some time to figure these things out really comes down to the biology of the virus itself. So the first thing that we can learn about and that we’re already getting some insight into is immune evasion. So we already know that one variant has a lot of mutations that make it a very good candidate for getting around our immune systems. And then the laboratory studies that allow us to determine basically how well our blood serum neutralizes the virus are things that we can do relatively quickly. So we’re already beginning to see that, in fact, the Omicron variant is able to get around at least some arms of our immune response, and it’ll probably be another week or so before we have sort of the full set of studies or at least the beginning of them to understand the response of our immune system to the variants.

The next thing that we’re interested in was transmissibility. The three things we’re really interested in with variants is immune response, transmissibility and severity, and we’re going to learn about them in that order. So transmissibility takes a little while longer because we really need to see the virus spreading in multiple locations with different types of underlying immunity, with different age distributions to really understand what transmission looks like. So we know that it can spread explosively in South Africa. But the question is, you know, to what extent will that repeat itself in other locations? And we can triangulate from the spread in a couple of different places to understand just how infectious is. And then the last thing, of course, is severity. And so that’s going to take probably on the order of another month to six weeks to really understand what the severity is. And that’s just because of the amount of time that it takes for a person to get severely ill with COVID 19. Despite the, you know, skyrocketing cases in South Africa, our best estimates for when the Omicron variant first emerged and started to spread was probably sometime in October, so it hasn’t had that much time to infect many people. Unfortunately, just need to wait for people to get sick, to show up to the hospital, for us to really get a good sense of how severe the variant is. So frustratingly, that may be one of the most important questions. The next one, we’re going to have to wait the longest to understand.

Q: And in terms of the surge that we’re in right now and you say we may have a surge within a surge. Should people be planning on, you know, going back to into quarantine businesses shutting down? Or are we vaccinated enough that we’re going to be able to get through this one without those tough restrictions?

STEPHEN KISSLER: You know, I think that’s the big question and one that we’re going to get some insight into within the next week or two as we understand the response of our antibodies to the Omicron variant. So my my hope and I think, is a realistic expectation that our T-cell immunity, which is one of the arms of the immune system that seems to be very much responsible for keeping people from getting severely ill, that seems to be a pretty broad spectrum response. And that’s part of the reason why the vaccines that were originally formulated still have maintained their efficacy against Alpha and Delta. Now, Omicron is probably the most formidable variants that the vaccines have seen so far, so we still have to wait and see. But I do have a reasonable amount of hope that that particular type of immunity will also be effective at keeping people safe from the Omicron variant. And so I would say I’m cautiously optimistic that we won’t need to go into the wide scale lockdowns that we saw during early 2020. But we do know that this virus has given us many surprises. And so I think we should have a lot more information about that within the next week or so.

Q: Thank you, Doctor. Appreciate it.

STEPHEN KISSLER: Sure. Thank you.

MODERATOR: Next question.

Q: Nicole and Dr. Kissler, nice to see you again. One of the ways we’re keeping people out of the hospital who do come down with COVID is by giving them monoclonal antibodies, and that is fine, except that it does prevent you from getting a booster shot for 90 days. Given what we just heard from you about the possible immune evasion of this new variant. Do you think that we should be more judicious about using the monoclonal antibodies for those who come down with COVID, given what we may be facing in the coming weeks with this new variant?

STEPHEN KISSLER: So all of this caveated by the fact that I’m an epidemiologist and not a clinician, so it’s hard for me to come out and give  clinical guidelines because that’s really one of the key things. So I think once a person reaches a point where they need monoclonal antibodies, I think that, you know that it makes sense to give them. By that point, usually a person is is relatively sick. And so I would say that if a doctor is giving them, then that’s probably for a good reason. Definitely. Getting those antibodies delays the time from which you can get a booster. But my hope is that that person’s infection will sort of act as at least a temporary booster until they can get the actual injection. So it’s definitely true that immunity from the virus itself does also provide protection and in some cases, very good protection against reinfection and severe disease later on. So I don’t think that delay between administering monoclonal antibodies and getting a booster vaccine should necessarily change the way that we treat the monoclonal antibodies. The Omicron could, of course, change our relationship with the monoclonal antibodies because it does seem like the variant is able to essentially again to mess up those antibodies ability to neutralize the virus. So we’re going to have to reformulate some of those antibodies to make them more effective against the variant. But for now, I wouldn’t suggest changing any of the clinical standards of care.

Q: Thank you.

MODERATOR: Next question.

Q: Hi, thanks so much for holding this. We all appreciate you taking the time. I was wondering if you could talk a little bit more about the third aspect of the things we’re interested in the severity of disease. Can you delve into a little bit further? Like what kind of data specifically we need for this, what the factors involved are? You know, why is it so difficult and why does it take the longest amount of time for this? And then my second question is just about rapid COVID testing. We get these questions from readers about kind of various topics, and the question this time was what is the best rapid COVID test?

STEPHEN KISSLER: Oh, interesting. Yeah. All right, so I’ll try to take those and turn. To expand on this question about severity, there are a couple of reasons why it took so long and then to get to your question about what sorts of data we still need. One of the things that was really alarming about the Omicron variant early on was that we were able to sequence its genome, and we saw that a lot of the mutations that it had been previously verified, either through other variants or through laboratory experiments to either enhance transmissibility or to allow it to evade our immunity. Now the difficulty here is that we actually don’t have a very clear sense of what biologically and physiologically. Leads this virus to cause severe disease. Our physiological understanding of that entire process is a lot less clear than what makes the virus transmissible and what makes it interface with our immune system. So the first thing is that there aren’t really any mutations we can point to say this is going to make the virus more severe. This is going to make it less severe, which we can do with transmissibility and with immunization. So that’s part of the difficulty is that, you know, there’s nothing about the virus genome itself that allows us to make these sorts of entrances. We just have to see how it behaves in the population overall.

And then complicating these things is, of course, the huge gradient of risk in severe disease from this virus by age. So one of the things that I’ve been thinking about a lot with it’s early spread in South Africa is that South Africa actually has a very low median age in their population. Their population is skewed much more towards younger people than many countries in Europe and indeed the United States. So we can imagine that even if the Omicron variant looks somewhat less severe, spreading in a context where there are many young people once it reaches populations, where there are potentially more older people, more people who are have extensive comorbidities, it might have a very different sort of severity profile. And so we’re going to really have to see how the variant behaves in locations with different age distributions and also in locations that saw different exposures to previous variants. So one of the other things that makes South Africa a little bit unique is that they saw a major wave of the beta variant, which we really didn’t see much of at all here in the United States. So some of their preexisting immunity is also against a different variant than our preexisting immunity here in the US. So that may also complicate both transmission, but then also the severity of the disease. So we’re going to have to be looking at all of that about how the virus behaves in different age groups, in different populations to really understand that severity. Is that right? Are you happy to be on to the next one or can I clear anything up?

Q: Yes, that was great, thank you.

STEPHEN KISSLER: And then, with respect to the rapid tests, as far as that specific question of which one is the best, it’s I mean, it’s the one you can find on the shelves at your local store. And most of the antigen tests, as far as I can tell, have pretty comparable sensitivity and specificity for detecting SARS-CoV-2. The things in my mind that most distinguished the tests are ease of use and in the amount of time basically that it takes to get a result. So I’ve got a number of rapid tests here that I’ve picked up, basically because I’ve just wanted to test the different brands that are available. I tend to like the tests that give me the results sooner because oftentimes if I’m using a rapid test, it’s because I’m on my way somewhere and I want to know whether or not I’ve got the virus. So a test that gives me a return in 10 or 15 minutes is a little bit more convenient for me than a test that takes an hour. And the tests also differ to some extent in really just how you use them. So, you know, with the Abbott BinaxNOW, you end up with this little card that looks like a popsicle with the swab sticking out, which is convenient in some ways. But I’ve actually found it a little bit difficult to sort of maneuver the swab, whereas others where you’re actually using a little vial and you just have a test strip that you can drop in. I find a little bit easier to use, but it’s sort of a matter of personal preference. So in my mind, those are the main differences. And with respect to ability to detect the virus, as far as I can tell, there might be small differences in the actual analytic sensitivity values that they reported. But for me, they’re more or less the same.

MODERATOR: Are you all set?

Q: Yes, thanks so much.

MODERATOR: Next question.

Q: Hi, thank you. I’m wondering, do you want to see colleges put in any new or different COVID-19 protocols right now? Thanks very much.

STEPHEN KISSLER: Thanks. So it depends on the college and sort of what they’ve already got in place. With educational settings, I mean, I’m a big proponent of frequent testing. And so if a college is not already testing people frequently and I’ll get to what I mean by that, I think that would be the first place that I would recommend making a change. Of course, encouraging vaccination, I think, goes without saying, but with frequent testing. I think that it depends a little bit sort of which population you’re looking at. So for undergraduates who may be living together, it makes a lot of sense to test them multiple times per week, two to three times per week. For others who may not be in as close contact with others, maybe testing weekly or so is OK. Doing that with PCR tests, if you can get a fast enough turnaround is great for rapid tests, I think are a great option for this as well. So the only thing that I would really recommend in educational settings and especially in higher ED, is that if you are doing tests frequently, get that started. I think that’s about it.

Q: Would you recommend boosters? Would you recommend mandating a booster shot?

STEPHEN KISSLER: Oh boy, I don’t know if I’m going to comment on that either way, because I think that, you know, of course. So maybe the way that I can say it is that as an epidemiologist, all of the data that I’ve seen supports the safety efficacy and really ultimately the value of getting a booster across the age groups for which it’s been approved. So full disclosure, I’ve gotten my booster. I’ve recommended to basically everyone who’s eligible to get a booster to get a booster because as far as I can tell, the booster frankly just reduces your risk, and I’d much rather be faced with a booster, the virus itself. But when it comes to mandates, I think that there are a lot more elements in play here that I’m frankly not qualified to speak on at all, so epidemiologically and clinically, I think it makes a lot of sense. But when it gets into the sociology and ethics of it all, it’s a lot murkier for me and I can’t really come down on one side or the other. But I can say that the scientific, epidemiological data suggests that I think they’re a good idea.

Q: And then so one more quick question, with the testing recommendations you had, do they also apply to vaccinated people, vaccinated students?

STEPHEN KISSLER: Yes. Yes, absolutely. So that’s one major thing is that especially with the emergence of Delta and even more so now with the Omicron variant. Certainly with Delta, it does help prevent you from getting infected in the first place and from spreading infection. But there are plenty of breakthrough infections. There have been outbreaks among fully vaccinated people. And so I see vaccination and testing as complementary approaches that actually help reinforce one another and not at all is mutually exclusive.

Q: Okay, great. Thank you.

MODERATOR: Next question.

Q: Hi, Dr. Kissler. Thank you for hosting this, and Nicole, thank you. I got two quick questions. As a follow up to a previous question, how should people be using the at home antigen tests to prepare for holiday travel and gatherings? And are they a replacement for rapid testing or PCR?

STEPHEN KISSLER: Yes, OK, so using the rapid antigen tests for the holidays. So I think one of the big changes that affects basically everyone here is that the updated guidelines to have a negative test within 24 hours of travel. So I think that rapid antigen tests are very good for that. The ways that I would recommend using rapid antigen tests is really as a screening method. So any time you’re going to be in a large group of people, I would encourage everyone who’s attending to take a rapid antigen test beforehand. The main value of those tests is that they can be done at home and they can be done quickly. The difficulty with PCR is that by the time you get the test back, oftentimes the result that it gives you is no longer very meaningful. If it takes a couple of days for the result to come back, that’s plenty of time for you to either have been newly infected or to have had an infection that was previously undetectable by PCR ramp up into something that’s infectious. So for the rapid test, test as close as you can to the thing that you’re testing for. And I think that’s the best thing that we can do. I think that can be immensely valuable for that. Of course, they don’t bring the risk of bringing infection to a gathering down to zero, but they do reduce the odds by an awful lot.

Q: Great. Thank you. And my second question is how does the Omicron variant change, how we should think about and prepare for breakthrough infections? And do we know if they’re going to become more common?

STEPHEN KISSLER: Yeah. So I anticipate that breakthrough infections will become even more common with the Omicron variant. And that’s based again off of some of the early information that we’re getting from South Africa, where that country just went through a really major delta wave. And so even though their vaccination rates were relatively low, they had a pretty high degree of preexisting immunity and Omicron has still been very much able to spread. Many of the cases of Omicron that they’ve been seeing have been in either vaccinated or previously infected individuals. So I do expect to see a lot of breakthrough infections with Omicron. And so then the question is, as you say, what do we do with that? I think that this kind of gets back to the question from that we were talking about with higher education settings where I think it makes testing all the more important. So with Omicron, I expect that vaccination will still help prevent against severe disease. But we may end up in a scenario where really vaccinated people are able to spread the variants almost as easily as unvaccinated people. I think that’s a pessimistic scenario, but I think it’s a realistic scenario but one that we’ll still have to verify with data moving forward. So really, I think that we should expect to see lots of breakthrough infections and we should expect to therefore ramp up testing because I think that’s really going to be our first line of defense against the spread.

Q: Thank you so much.


MODERATOR: Next question.

Q: Thanks very much for the call, and thank you, Dr. Kessler. So I have another rapid antigen test question. So as these rapid tests become really mass phenomena that we see, you know, everyone trying to get them before Thanksgiving, a whole statewide program in New Hampshire, how much of a dent do you think they can actually make in a surge? And second question is, do you foresee rapid home testing becoming a very common phenomenon for things like flu and other viruses? Thank you.

STEPHEN KISSLER: Sure. Yeah. So this is this is one of the Age-Old challenges in epidemiology is that we never really get to see what would have been. And part of the reason that I and many of my colleagues use mathematical models is because they allow us to get some sense of that question. They allow us to compare alternative realities. And in this case, this has to do with testing. So, you know, the question is, if we have these tests, will it prevent a surge from happening? It may not prevent it entirely, but I am absolutely convinced that it can prevent surges from being as bad as they might have been otherwise. You know, for all of the reports that we see of rapid antigen screening before gathering sailing, there are probably 100 other gatherings where they worked, but we never really get to hear about those. So I think that these rapid tests can go a long way towards preventing spread in large gatherings, and that’s really the fuel of the fire for this pandemic. We know that super spreading events where a single infection infects many others. Really drives the spread of this virus hugely, and rapid antigen tests can really reduce the odds of something like that happening. So yes, I’m absolutely convinced that they’re helpful. It’s difficult to point to clear data from the spread of diseases just because we can never really, I guess I’d see what could have been otherwise. But the theory, the mathematics and some of the data that we do have from countries that have rolled these out on a large scale do suggest that they have helped.

Q: I just to interject for one second, but we do see the UK and Germany having big surges despite having really robust home testing programs.

STEPHEN KISSLER: Right. And so I think that, you know again, that gets to the question of what would have been without them. And I think that that’s something that we don’t get perfect insight into. But I think that there are two things here. So one is that we, those surges, may well have been much larger even than they would have been in the absence of those tests and larger, potentially in different ways. So one of the things the tests can help do is sort of aid us in this going way back to 2020 of flattening the curve. So even if it doesn’t totally prevent a person from ever getting infected, it can keep them from getting infected as soon because maybe they avoid a gathering or maybe the person who’s would have infected them and avoids the gathering. And so once there’s a lot of spread in the population, it’s really difficult to eliminate transmission, no matter how many rapid tests you have available. But I suspect that the surges would have been even larger without the use of those rapid tests. Now that said, I think that there does need to be a much clearer guidance on how to use the tests, when to use them, what to do with the results as well, in the sense that these tests are really best for screening right before a gathering. And but a negative test really doesn’t clear you for very long. It basically prepares you for that day and maybe the next day then you need another test to sort of clear you again. And I think that that’s one of the messages that maybe hasn’t gained as much traction as I would have liked for it to. And maybe one of the reasons why the surges have been as large as they have been.

Q: Thank you. And in terms of going forward for flu and stuff?

STEPHEN KISSLER: This is one of the things that I’m actually most excited about with the advances in technology that have come about during the COVID-19 pandemic. I am hopeful that we will have cheap, rapid antigen tests available for other pathogens, especially respiratory pathogens like the flu. And I think that that will hopefully help us to keep those other viruses better under control as well. I think it could go a long way towards keeping schools running smoothly, keeping workplaces running smoothly. I think that there’s a huge amount of opportunity there.

Q: Thank you.

MODERATOR: Next question.

Q: Hi, there. I just have a quick question about, and I understand this is all a lot we don’t know, but with this idea that it may be more mild, Omicron, but we know we’re seeing these really worrying estimates about how transmissible it is coming out of South Africa and England. I mean, how could that then kind of affect our, you know, I guess how worried should we be, you know, and how on a population level, you know, even if it’s milder, but it’s a lot more transmissible because that kind of outweigh any, you know what I’m saying, any sense of relief we have because it’s not as severe.

STEPHEN KISSLER: Yeah, I mean, I think I think you’ve hit the nail on the head there. So I am definitely concerned about the spread of Omicron and it really comes down to its ability to spread so rapidly, even in a population with underlying immunity. Its earlier on in the pandemic. One of my colleagues, Adam Kucharski in the U.K., who posted sort of a thought experiment on Twitter that I found to be really illuminating, and I think we can sort of walk through it here too, which is that if you could have a variant that was 10 percent more severe or 10 percent more transmissible, which would you choose? And your intuition might say that you would rather have something that’s more transmissible but equally severe. But you’re exactly right that because of the nature of exponential growth with a variant that’s 10 percent more transmissible, you end up with a far larger total number of infections, hospitalizations and deaths than you would with the variant that was 10 percent more severe. So for me, transmissibility really is the key to this virus. And so unless it’s much less severe than things that we’ve seen previously, which I think is unlikely, I think that it will still cause quite a bit of strain on our health care systems and really be something we have to contend with in the coming months.

Q: OK, thank you.

MODERATOR: Next question.

Q: Hi, thank you for doing this. We continue to change a lot of questions here in our newsroom about COVID boosters, and I know you’ve talked about that a little bit today. Can you talk about why we may be seeing some of this confusion over Booster still? And can you address some of the specific questions or confusions about what you’ve heard? And finally, we got one specific question as something you could answer because we’ve been getting it a lot lately is should people hold off on getting their booster in the event of the creation of an on the Omicron specific one?

STEPHEN KISSLER: Yes, thanks for those questions. Yes, there has been a lot of confusion about boosters. My sense and I actually be curious to hear your experience as well because I mean, frankly, it would be helpful to me to hear a wider range of what people have been thinking about and curious about with respect to the boosters. But you know, one of the key things is that, early on, the boosters were recommended for people who are vulnerable and people who are in high risk transmission settings. And then lately they’ve been. OK for everyone, and then more recently, with the emergence of Omicron recommended for everyone, so part of the reason for the shifting guidelines is the shifting context underneath. So again, earlier on the data was very clear that people who are very vulnerable to diseases could benefit from a booster for the same reason that I was talking about earlier that it takes some time to understand the severity of the Omicron variant. Sort of the same principles are in play for why it takes some time to understand the vaccine benefit for people who may have less to gain from it. So those data were still coming in and was part of the reason why it wasn’t initially recommended for everyone. Those that have since come in, it does seem like it’s a good idea for basically everyone who’s eligible to get the booster. It really does improve their defenses against the virus. And now, of course, with the Omicron variants, we’re in the sort of difficult setting where we have to make policy decisions in the absence of complete data. So we don’t we don’t yet know completely to what extent the boosters help protect us against severe disease from the Omicron variant. But we do have very good immunological reason to believe that getting a booster will be our best defense against the Omicron variant and that it will at least be better than nothing, or at least not having a booster. So that’s really behind these changing guidelines and getting more data, the emergence of the Omicron variant. And unfortunately, it’s led to a lot of confusion, but hopefully understanding it in terms of that shifting context underneath all of this is maybe helpful. I’d be curious before I go on to holding off on the boosters, are there any other things that you’ve heard that people would like addressed specifically?

Q: Oh, there’s a long list. Yes, I mean, but I think what you’re getting at is exactly the kinds of questions that we’re hearing, too, but we are getting some more specific questions, like if I’ve got a cold, should I get a booster? All sorts of different things like that.

STEPHEN KISSLER: Yeah. Well, there’s loads of things and I mean, I have a lot of sympathy for that. It’s a confusing time and with that one specifically, I would say absolutely, yes. It seems like getting a booster. Its efficacy isn’t affected either way by having a cold, just get a COVID test beforehand, you know? And yeah, so hopefully, hopefully that helps some. And if there’s any way I can help with follow up, I’d be happy to do that too. With respect to holding off for an Omicron specific booster, I would recommend against that. I would say that if you’re eligible for a booster and are interested in getting one, I would highly recommend getting one now because by the time we formulate an Omicron specific vaccine and get it approved and get the supply ramped up enough to administer to everyone who wants it. So will already done it will have already done basically what it’s going to do. It might be continuing to spread after the fact that we’re going to see a surge of Omicron, almost certainly in the coming weeks to low numbers of months, and we’re not going to have a specific booster in that time, unfortunately. So I really think that the best protection that we have against Omicron right now is that booster of the vaccine that we have currently available. And if you’re going to get a booster, I would say, don’t wait.

Q: Thank you so much.

MODERATOR: Next question.

Q: Hey, there. Thank you so much for taking my question. What kind of looking at some of the things you mentioned? You don’t say we need to go back to shutdowns completely, but what about some of the travel restrictions? Obviously, there are restrictions on international travel. Should there be some on domestic travel, as you mentioned in a couple of weeks, we’re going to learn more. But that’s also the height of holiday travel season and I have a follow up.

STEPHEN KISSLER: Yeah, thanks for the question. So I tend to follow this side of thinking that travel restrictions are extremely costly and should be very much a last ditch effort. I think now that we’ve seen documented spread of the Omicron variant in many different countries, including here in the United States, I think that to a large extent, those international travel restrictions ought to be lifted. And that’s in part because those travel restrictions are actually hindering the science from taking place that we need to do. They’re extending those delays in getting the answers to those questions that we were talking about in the first place because it’s more difficult to share reagents. It’s more difficult to share the tools that we need to answer these questions. And so I think that definitely travel restrictions in an early emerging epidemic can delay the spread of a pathogen because they can keep it out for a short period of time. But I think that ship has sailed. Now, with respect to domestic travel restrictions, I also am generally not in support of them. I think that we have better tools available to achieve the same goals, and those are specifically rapid tests before we travel. I think that everybody should be taking very rapid test immediately before getting on a flight. Basically not traveling if they get a positive test, but otherwise, I think that that can do everything that we hope to do with travel restrictions without actually imposing the restrictions.

Q: And then everyone is kind of touched on boosters and even Omicron related boosters. Could we foresee a time when we need like a fourth shot because we have more variants and do we need to even redefine what fully vaccinated even means moving forward?

STEPHEN KISSLER: Probably so. And, you know, this is we’re in this really odd period of time trying to understand sort of what the outlook for vaccines is going to be. I know prior to the emergence of Omicron, I was hopeful that this third dose might be either the last one or the last one that we would need for some number of years, I think. And that follows on from, you know, we have a number of other vaccines against respiratory diseases and other diseases that we get when we’re young kids, there’s maybe three to four doses that are spaced apart by about six months. And once you do that, you’re essentially protected for life. So our immune system is very good at taking these repeat spaced out exposures to an antigen through a vaccine and giving us very long term protection. The reason we need a flu vaccine every year is because the flu keeps mutating to a large extent. And so we end up with basically a new flu strain, and so we need our vaccines to update to keep control of that. So the big question was, is SARS-CoV-2 going to fall in the flu camp or is it going to fall in the camp of these other viruses that are more genetically stable so that we won’t be frequent boosters? Initially, I thought that it was going to be much more stable, but Omicron is really causing me to rethink a lot of this. And so I think that I’m now beginning to move on the side that we’re going to need more frequent boosters, hopefully not annually, but maybe on that order. Much like the flu. And I think that if that becomes the case, then fully vaccinated becomes a term that’s sort of less useful because there is no sort of fully vaccinated as it just sort of are you vaccinated? Basically, how recently have you been vaccinated becomes the question. And I think that that might end up being the more informative measure.

Q: Thank you so much.


MODERATOR: Next question.

Q: Good morning, Dr. Kissler. Knowing that we have a ways to go before we learn about the severity of Omicron, what do we know now using data out of South Africa about how children fare against this variant and specifically kids who wouldn’t be vaccine eligible here in the U.S. under the age of five?

STEPHEN KISSLER: Thanks for the question, so we don’t know an awful lot. But I can share with you some of the information that we do know and that we’re trying to make sense of now. So there had been some earlier reports from South Africa suggesting that a an unusually large proportion of cases in the hospitals of COVID-19 were in children. That was initially alarming to me, but I think that there are two reasons for that, and one of them is that in South Africa, like here in the United States, young children are not eligible for the vaccine. And so they may not have the same degree of underlying protection. But another reason for that and sort of a word of caution when interpreting these statistics is that it turns out that a lot of the pediatric COVID-19 cases that were recorded there were actually in children who were in the clinic, in the hospital for a different reason, and they’d gotten a test for COVID-19 as routine. And it turned out that they were positive. But we’re not actually in the hospital for that reason. And so that really increased the that caused a greater number of cases in kids than would have been suspected just being caused by COVID-19. So it’s going to take us a little while to understand us. But as far as I can tell, there’s no reason to believe that the Omicron variant is especially severe for young kids. I think that if that were the case, we would already be starting to see a signal of that. And I haven’t seen that yet, or at least I haven’t seen conclusive evidence of it. My hunch is that it will probably fall in line with the previous variants, which has actually been really stable in this respect that basically it’s, you know, much less severe for very young kids and much more severe for older people that that sort of increase of risk with age has remained one of the few things that stayed remarkably stable over the course of the pandemic. So my hunch is that it will stay also the same with the younger crowd variants. But again, as with everything else, it’s going to take some time to determine, and it might even take longer to determine conclusively for kids again, because their risk of severe disease is so low that it’s just going to take a long time to accrue the number of cases that we need to make good statistical measurements of the relative severity in young kids of this new variant.

Q: Thanks so much.

MODERATOR: Next question.

Q: Thank you for taking my question. So I just wanted to confirm. Are you saying that Omicron overtaking Delta is essentially inevitable? And I saw that Trevor Bedford tweeted that he thinks we have about eight weeks before we could see an Omicron driven surge. Do you think that timeline is roughly accurate? And then my last question is, do you think the Biden administration is doing enough to prepare if that is the case?

STEPHEN KISSLER: Sorry, I’m just jotting these down to make sure that I address each. So I do expect Omicron variant overtake Delta, probably around that time frame that you saw quoted in Trevor Bedford’s tweet thread. So initially, with cases coming out of South Africa, I wasn’t sure because Omicron emerged in a context when there wasn’t much Delta spreading. But there had just previously been a major Delta surge. So presumably if Delta had been protective against Omicron in a very large way. And I mean, protected against onward transmission of Omicron, I don’t think that we would have seen as rapid increase of Omicron in South Africa as we have. And now we’re also getting some data from the UK where we’re seeing pretty rapid increases in the s gene target failures, which is a pretty good indicator to Omicron, despite the fact that there’s plenty of delta spreading there, too. So it seems like Omicron can spread very happily in places that have either seen a recent Delta wave or that are undergoing a current Delta wave. And so I do actually expect no crown to displace Delta in the coming weeks. I think that, you know, the time frame for that is going to vary quite a bit in places that have already started to see increase in transmission. I think, you know, within the next six to eight weeks is probably reasonable. And, you know, I might even adjust some of Trevor Bedford estimates to be even a little bit sooner because by the time we’ve actually detected the variant, it’s probably already been in circulation for a little while, and so it’s already a little way into that eight week period. So unfortunately, you know, just in time for the new year, it’s likely that we’re going to see quite a bit of a crunch spreading. But also sort of a caveat to that is that throughout the pandemic, we’ve seen really remarkable differences in the timing of outbreaks in different places. In many ways, the UK has actually sort of preceded the US in many of its waves. And even here in the United States, there’s been a lot of variation in which states, which regions have been hit at different times. So while I think that eight weeks is a useful rough estimate, I think that when we’re thinking about what’s going to happen in my community, there’s going to be a huge amount of variation that I don’t really know how to get a handle on. But I do think that probably most places can expect to see a major Omicron surge before the end of the winter.

Q: Thank you so much and just any thoughts on what we’ve seen from the Biden administration so far on preparing for that inevitability?

STEPHEN KISSLER: Yeah, thanks so much for taking those notes. Sorry about that. Yeah. So I think that oh boy, I feel like I sound like a broken record, but I’m encouraged by the fact that rapid tests are available and are going to be subsidized by insurance companies. But I do think that we could go even further, making them much cheaper, much more freely available, much more widely available and much more accessible. I think some states encouragingly are taking steps in that direction. But I do think that increasing capacity for rapid, frequent testing is something that I would hope the administration could do much better with. I do think that they’re sending the right message about vaccinations, so I think that that’s good. So basically one quibble in one voice of support. Thank you.

MODERATOR: Next question.

Q: Thanks. So I had two questions I’ll take, I think they’re sort of unrelated, so I’ll do them one at the time. The first was, I know you kind of generally said that when it comes to boosters, your advice is don’t wait. Given the number of breakthrough infections that we’ve seen in the past, like I’d say, like this fall, what would your advice be to people who had gotten a breakthrough infection and probably have some natural immunity within the last month or two? Like should they be waiting or should they be trying to get a booster as soon as possible?

STEPHEN KISSLER: Yeah. So I think that from everything that I’ve seen, more immunity is better than less. So if you’ve gotten a natural infection, they can actually put you in the position where your body has been exposed to sort of a slightly different version of the virus that is contained in the vaccine. I would still recommend it. I think that definitely, you know, that’s not to say that previous infection isn’t protective against  infection and severe disease and those kinds of things. But really, the more we can expose our body to these antigens and the more that we can expose them to diverse aspects of the virus, which is something that we can do with your natural infection and through vaccination. And then I think, I think the better so. So I think even if you’ve been previously infected, while that will give you some degree of protection moving forward. I just think a booster makes good sense.

Q: OK, thanks. That’s interesting. And then my other question. Hopefully, this isn’t redundant with what you said in your opening remarks. I was like five minutes late onto this. But just again, I’m thinking, particularly here in Massachusetts, where like over 70 percent of the population is vaccinated. What precautions should they be taking coming in headed into like the holidays and holiday gatherings just come back starting and with rapid testing? Or is there more that you were advising?

STEPHEN KISSLER: Yeah, I think definitely start with rapid testing start and then was even better. And, you know, I guess the suggestions that I’ve been giving for holiday gatherings. Pretty much stand even in the face of potentially spreading Omicron, which is so first line of defense is vaccination, so if haven’t been vaccinated yet, now’s the time to do it. Second line of defense is ventilation, so making sure that the indoor spaces are well ventilated because I think that that’s a very easy, cheap way to keep spread down, even if somebody does show up while infectious and then testing and doing a rapid test immediately before any gatherings. And also immediately before and after travel would make a lot of sense.

Q: On ventilation, if like you’re hosting like a holiday gathering at someone’s house once or a kind of practical steps on that?

STEPHEN KISSLER: So easiest thing is just open some windows. Six inches tends to be pretty good for getting some good ventilation in a room happily. So you know it’s cold outside. Maybe not right now in Boston, but certainly will be by that time. And the differential in temperature actually helps with air circulation. So when it’s warm inside, cold outside, you know, unfortunately that gives you a blast of cold air in, but that cold air is ventilation. And that’s so, so even just opening the windows by a little bit, I would say, you know, four to six inches can really help with that circulation if you want to go the extra mile. Setting up an outward facing fan can help. And so can sort of be the air filters with a HEPA filter, for example. You can put those in your homes as well, and those can just sort of help to filter some of the air that’s circulating indoors. So that’s what I would recommend.

Q: Great. That’s really helpful.

MODERATOR: Next question.

Q: I have a follow up question to my previous question about a and breakthrough infections. Does the presence of Omicron change how people should behave if they are currently experiencing a breakthrough infection? You know, I guess that would mean the potential that they may be carrying Omicron? Should they behave any differently?

STEPHEN KISSLER: You know, I would say no. Presuming that the person is already isolating and taking care of themselves and going to the hospital if they need it, but I think that in terms of a person who’s been infected with COVID-19. So first of all, if you have a breakthrough infection right now in the United States, it’s still very low probability that it’s Omicron, it’s almost certainly Delta. We’re doing plenty of genetic surveillance here in the US to know if a lot of virus is Omicron. And currently we have a lot more Delta than we do Omicron at the moment. So if there’s a breakthrough infection, it’s probably Delta. That said, I think all of the same things stand whether it’s Delta, Omicron or any other, you know, Greek letter or non-Greek letter of SARS-CoV-2, which is just once you know your positive, once you know you’re infected. Hang tight, limit your encounters with other people and just take care of yourself.

Q: Thank you so much.


MODERATOR: Next question, go ahead.

Q: Hey, thanks for having me on here. I don’t know if you’ve answered this, I kind of got on a little bit late, but can you talk at all about sort of big picture here? I mean, we hear about every new variant that comes up every couple of months. Is this one of those things where people should just kind of be in a space in which life has adjusted? Or are we still fighting to get out of the pandemic, whatever that means?

STEPHEN KISSLER: Yeah. Oh, boy. So I don’t know. I’m still holding out hope that we will reach a point where the virus has optimized, its ability to infect people and where it’s sort of rate of evolution and are generating these new, very different variants will slow down. And my hope, additionally, is that as that process continues, our immune systems will become increasingly accustomed to the virus, provide a greater degree of protection, will decrease the infection fatality rate, for example, the rate of hospitalization, and will make it so that it’s easier to live with this virus. So I’m still hopeful for a future in which. The virus doesn’t pose as much of a threat as it currently does. I am still again cautiously optimistic that we won’t be in sort of this carousel of variant after variants that sort of turns our world upside down. But to be perfectly honest, we don’t yet know for sure. As I mentioned earlier on the call, the virus has found all sorts of ways of surprising us. So again, based off of everything I’m seeing, I’m hopeful that we’re still in the pandemic and it will diminish at some point. But I can’t promise that.

MODERATOR: Are you all set?

Q: Well, I do have one other question and again, since I have been late, you may have answered this one. But looking at Omicron, kind of how is this different? I know that there’s been talk about people being more hopeful that this will not be a severe how is this showcasing that it’s different from Delta and maybe what that potentially say for the development of this in terms of severity of the disease in that part of the whole thing with the virus is that it wants to be able to spread can’t spread too much if you kill every host. Does this tell us anything about where this is going?

STEPHEN KISSLER: Yeah. So we know that the Omicron variant has a lot of mutations that are likely to make it more transmissible and to get around our immunity, which will help it to spread, and that’s part of why we have seen the explosive spread in South Africa. I am a little less optimistic currently about the relative severity of Omicron. I think that it’s just it’s just far too soon to say and that early reports of it being less severe while hopeful. And I want to believe with everything I am that they’re true. I just think that it’s so soon that it’s that I could equally see those reports being confounded by the fact that most of the early cases were in young people, by the fact that there just hasn’t been enough time for the severe cases to really develop. One could even imagine a scenario in which the variant is more severe, but it takes a longer time for the disease to progress. And so I think that there is still a lot of options on the table that we don’t really know about the severity of the crime with respect to sort of the principles of evolution that you’re talking about. So. It’s true that pathogens evolve to make them more transmissible. Basically, you know, if something is more transmissible, it will take over and that that is the process of evolution. So if there is a pathogen that doesn’t spread until after a person begins to show symptoms, then it has a very strong incentive to make those symptoms less severe. Because if it can infect a person and that person can not know it or that person can go about their lives, then it makes the pathogen more transmissible, which is really its bottom line. The trick with SARS-CoV-2 is that even from the beginning of the pandemic, most of the spread has happened either before a person knows they’re infected at all or shortly after when they’re still showing pretty mild symptoms. So the virus actually doesn’t really have much incentive to reduce those symptoms because it’s still able to spread quite happily, even while causing severe downstream illness. So I don’t think that there’s any evolutionary argument for why SARS-CoV-2 would necessarily evolve to be less severe. I think that if it does turn out that the Omicron variant is less severe on a per case basis, it’s probably just because we got very lucky.

Q: Thanks.

MODERATOR: Looks like our last question.

Q: Hi, guys, thanks so much for doing this. I have two questions. The first is not to parse what you’ve been saying, but I haven’t heard you say the word mask either talking about college students or at parties and just wondered first what you think about masks and why you haven’t uttered that word?

STEPHEN KISSLER: Yes. I mean, if I can respond to that, that’s kind of funny. So I feel like at this point, I. I haven’t mentioned masks because I also don’t mention like putting on pants in the morning. It’s such a central part of what I do that I think that. Wearing masks indoors absolutely makes sense. The best mask that you can get your hands on. So. Yeah, sorry about that.

Q: No, that’s OK. I just want to make sure you weren’t hesitant in some way about masks. And the second question is, you started talking about this earlier, but I’d love you to go into it a little bit more. What do you see? What are you hoping for vaccines, for the future that we will not need them on a regular basis? What else do you want them to be able to do or think that they might be able to do to plan for it?

STEPHEN KISSLER: Yeah. So I’m actually hopeful. So we’re in this period of time where we’re thinking about it on a specific vaccine. But one of the early promises of the mRNA vaccines is that they might be we might be able to rapidly update them. Part of the reason we can’t do that right now is because we don’t have the regulatory processes, but we do this already for flu, to some extent. So one of the things that I hope for is for if we needed a vaccine that is updatable every year or to be very specific to the thing that’s circulating and that is tied together with a couple of other respiratory viruses as well. So I would love to be able to get a joint flu COVID vaccine every year if that becomes, you know, if the epidemiological data bears that out. And so I think that there are some decent promise for that. This is a little outside of what you had mentioned, but I think that I’m also very excited about some of the antiviral therapies that are coming out against SARS-CoV-2. And I think that some of the technology developments that’s been going on for those may also help against other respiratory viruses, too. So I think that all of these things will sort of help the outlook as we go forward.

Q: Great, thanks, and do you see mRNA vaccines having a role in other diseases as well?

STEPHEN KISSLER: Absolutely. I mean, you know, I want to be cautious. There’s that famous innovation curve and excitement about innovation where we have this new discovery and it works really well. And so we think it’s going to solve everything. And then there’s the period of disappointment when it doesn’t actually solve everything. And then a little bit thereafter, we sort of reach this medium where it’s, you know, part of our lives and solve some things, but there’s still some other problems. So I’m still pretty hopeful. I think that many vaccines will open up a lot of opportunities to address different sorts of infectious diseases that we haven’t really been able to manage before. The mRNA vaccines specifically allow us to have highly targeted vaccines. Apparently, vaccines that are very well tolerated and vaccines that are easy to update. So my hope is that we’re going to start to see many vaccines against a whole lot of things, and I’m cautiously optimistic that it’ll be pretty successful. I hope, too, that we can start looking at other emerging infectious diseases too. One of the things with mRNA vaccines, is that we might even be able to develop these vaccines against pathogens that are currently relatively rare, but that are of endemic potential to try to stay one step ahead of them. And since we can sort of formulate the vaccines relatively quickly. Yeah, my hope is that we’ll be able to start doing that, too. So rather than sort of being in this reactive stance, we’ll sort of be proactive and have an arsenal of vaccines available that might be effective against things that might go on to infect large numbers of people in the future.

Q: Perfect, thank you so much.


MODERATOR: Dr. Kissler it is 12:01, I think that was actually our last question. Do you have any final thoughts for us before we go?

STEPHEN KISSLER: No, I think I think you’ve extracted all the information I have.

This concludes the December 7th press conference.

View more press conferences