COVID-19: What We Know (and Don't Know) About the Delta Variant
This article is part of an ongoing collaboration between the Colorado School of Public Health, the Denver Museum of Nature & Science, and the Institute for Science & Policy. Find all of our previous COVID-19 webinars and recaps here.
Despite a springtime vaccination boom that allowed for broad relaxation of masking and social distancing guidelines, the United States finds itself at a COVID-19 inflection point once again. The ascendent Delta variant has brought a spike in cases and hospitalizations, particularly in areas of the country where lingering vaccine hesitancy has slowed inoculation rates.
Dr. Jennifer Nuzzo, Senior Scholar at the Johns Hopkins Center for Health Security and an Associate Professor at the Johns Hopkins Bloomberg School of Public Health, joined Institute Director Kristan Uhlenbrock to cover the latest on vaccines and variants, plus examine what we know so far about breakthrough infections and the ongoing effort to bolster vaccines to keep pace with new mutations.
This transcript has been edited for clarity and flow. To view a recording of this discussion, click here.
KRISTAN UHLENBROCK: Dr. Nuzzo is a Senior Scholar at the Johns Hopkins Center for Health Security, and an associate professor in the Department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health. She is also a senior fellow for Global Health at the Council on Foreign Relations. As an epidemiologist by training, her work focuses on global health security, including a focus on pandemic preparedness, outbreak detection and response, global health systems, and infectious disease. She is extremely accomplished in so many ways, I'm not doing it justice. She's frequently in the news and media, so you may have seen her there.
Good afternoon, Jennifer. How are you doing today?
DR. JENNIFER NUZZO: Thank you, thank you for that introduction. Thanks for having me. It's a real honor to join everyone and I’m encouraged that people in the sunny days of August still want to hear about COVID after this past time but happy to have this conversation today.
I just wanted to give some framing remarks and set the stage where we are when we're talking about the variants or we're talking about the vaccines. And just a quick recap of where we are in the U.S. At any rate, we’ve crossed the threshold of 38 million cases being recorded, and over 630,000 deaths in the US. You can see the weekly case average, and unfortunately, we are in a period of continual increasing in terms of the weekly cases that are being reported in the United States.
Unfortunately, for the first time in a long time, deaths are on the upward climb as opposed to the downward climb. So this is obviously a disappointing situation to be in given that, you know, a couple of months ago things were -- I won't say looking up because they were actually looking down, they look much more encouraging and optimistic than they do now. Unfortunately the situation that we're in right now is that the U.S. epidemic is worsening in many states. Certainly Louisiana, Mississippi, Florida, Alabama, Georgia. Those states are certainly in the news we're also hearing a lot about concerns in Oregon. Conversely, we're hearing, less about the Northeast, and in other parts of the country.
Case numbers are increasing, almost everywhere. And part of that is that even within states that have high vaccination coverage, there's still gaps in immunity, there are still pockets of people who are not vaccinated and they remain susceptible to outbreaks. Certainly the states with the lowest vaccination coverage, are now seeing the highest number of cases. That seems to be quite clear the data, but I think it's a warning to all states that when you have some pockets of immunity -- if you have, you know, neighborhoods within counties or even whole counties that are not well vaccinated, that you may continue to seek case increases, unfortunately.
There's a lot of variation across the country in terms of vaccine uptake. At the state level we see it, but we also see it within states. And so that's important for interpreting things like how was it that Los Angeles was having a rise in Delta a couple of months ago when you know California on, on balance is one of the higher vaccination states. And at the time when Los Angeles was seeing the rise in cases, they had about 60% overall vaccination coverage. It's grown since then, which is good, that we've seen more vaccine uptake since then. But if you kind of scroll down to the neighborhood level, there were neighborhoods where the uptake was much much lower, and people socialize within their neighborhoods, they socialize within their networks, and so if you have susceptibility, networks that are susceptible, if someone gets infected, they're likely to spread it to others.
The good news is actually vaccination uptake has increased quite a bit since we've seen the rise in Delta, including in the states that have been hardest hit. So people are starting to think that being on the fence about vaccines probably isn't working out so well. And we're seeing more people sign up for the vaccine. So that’s encouraging
A lot of questions about whether the vaccines are still working and whether or not they're still working against Delta. You may have seen statistics, overall statistics, even though the CDC showed vaccine effectiveness before Delta vaccine, vaccine effectiveness after Delta and there was a big step down. And they had an overall percentage. I'm not showing that graph because I actually think it's quite misleading. And I think it's pretty easy to be misinterpreted. I just wanted to kind of cover the basics of what is vaccine effectiveness because I found that a lot of people even, you know, very scientific, scientifically savvy people sort of misinterpret it.
So the most important thing you should know is that when you hear something like the vaccine is 80 or 90% effective, what that means is they're comparing a group of people who are vaccinated, to people who aren't. So it’s a relative measure, it's not an absolute measure. Sometimes I hear people say, if you have a vaccine that's 80% effective, that means, if 100 people are exposed 20 of them will get infected. And that's not true. It's just they're comparing the vaccinated people to the unvaccinated people, and that relative measure is really important.
And also, if you can think about what factors could influence both vaccinated and unvaccinated people's likelihood of getting infected, you can imagine that there are a lot of different variables. If you're older, we know that older folks sometimes don't respond as well to vaccines. That’s one reason why they get a stronger flu shot. We know that if you've been infected before, you probably have more protection than somebody who wasn't. Certainly, there are demographic factors. In my view, one of the most important ones that we should all keep in mind, when there are higher levels of virus circulating in the community, everybody, including vaccinated people will have a higher probability of coming in contact with the virus. So the likelihood that they're going to be protected is different when the virus is hard to find, versus when it's all over the place.
Of course, there's all sorts of other more biological things. You may hear different numbers coming from different countries. You may hear different numbers even when the trials were happening, and we were hearing about the results from the clinical trials. We call it vaccine efficacy when it's in the context of clinical trial but in the context of real world data, its vaccine effectiveness. The relative definition is the same whether its efficacy or effectiveness, but you would hear different data for different vaccines and some people would try to pick the vaccine that they thought has a better number, when in fact it was really comparing apples to oranges because those vaccines were studied in very different populations at different points in time and so even a vaccine that is the same could come up with a different number if it's studied at a different point in time or a different population. So just to maybe say, don't get too hung up on the numbers, particularly when comparing countries because there are a lot of factors that go into that. We have to understand what those factors are in order to understand if we should be concerned about the vaccines or not.
If you listen to nothing else from this presentation, the vaccines that we have are still doing the thing that we need them to do, above all, which is to keep people out of the hospital, and to keep them from dying, to prevent severe illness and death. This is basically why we develop these vaccines. This is the key feature of COVID-19, and the virus that causes it SARS-CoV-2, that makes us so concerned about it. If SARS-CoV-2 weren't capable of putting people in the hospital or killing them, most of us would have never heard of it. So the good news is that the vaccines are still doing what we need them to do and this study that I'm showing is a recent one from New York, looking at how the vaccine has protected people from hospitalization. Over time, still very high levels of vaccine efficacy and effectiveness. Among people regardless of when they were vaccinated against hospitalization and death. So good news.
That said, there are some observations that the number of vaccinated people who are coming down who are infected -- what we mean by effective is either that you have no symptoms and you tested positive, or you have symptoms and you tested positive -- that percentage seems to be changing. So the percentage of people who have cases, who are vaccinated, is increasing, which is something that we actually expect as we vaccinate more people. If you do overtime to vaccine 100% of your population, if you had one case, 100% of your cases would be in the vaccinated person, right? So we do expect that the percentage of cases who are vaccinated to increase over time.
But nonetheless, we are seeing an increase in infections among people who are vaccinated. And one of the questions is: does that mean the vaccine is not doing the same job that it was doing earlier? Now, if the answer to that is yes, there could be a few reasons. One could be that the vaccine just doesn't work as well against Delta. Or it could be that you got vaccinated but now your immune response to the virus is less robust because it's been some time since you’ve gotten vaccinated.
There's also another interpretation and at least based on the United States data and I'm preferentially only showing you data here from the United States because of what I said before, that it's really hard to compare studies from different contexts. At least in the United States I am less worried about people's immune systems not doing a good enough job. We know that the United States people over the age of 65 are the ones who got vaccinated first. So if it were something about their immune system not quite doing what it's supposed to be doing, you would think that we would see it in that group, too.
My colleague David Dowdy at Johns Hopkins pointed this out, I want to give him credit, that perhaps there's something else going on. Perhaps it's about behavior and the fact that you know we did a whole lot of new things. Remember I said one of the most important things is if there's a whole lot more virus around, you have, there's more probability of coming in contact with it. And so if you're under the age of 65 and now it's few months after you've gotten vaccinated, you're ready to get your life back. You hear people talking about the summer of being vaxxed and waxed. At the same time masks are no longer required. It may not be entirely surprising that we'll see more infections, and, you know, potentially, disease in people who now have just more opportunities to be infected.
I think it’s important to understand that the immune system has multiple components and I'm not an immunologist. You're going to get like the epidemiologists, very high level explanation of immunology, but the key takeaways here is that there are your antibodies and those are usually the things that react first, and then you have your cell-mediated immunity and your things like your T cells and your B cells and those are the things that usually click in, kick in later, but are really good at helping to protect against serious illness. Both of those components of the immune system, all the components of the immune system -- they're designed the immune system is designed to ramp up when it sees an intruder and then after the intruder is gone to kind of calm back down. You don't want to be in a state of constantly heightened immune response. There's some downsides to that.
So it's not surprising at any point -- and particularly the longer it's been since your vaccine -- to have your immune system, have your antibodies decline. But the question is, is that a problem? Well, there is some thought, if perhaps one of the reasons why we're seeing, we're hearing about more people now who are vaccinated, getting sick. You've probably heard about somebody that you know who was vaccinated, but got sick and they felt lousy for a few days. Perhaps that is because their antibodies have waned a bit. It's possible. I don't think we see a great, compelling case for this in the data for healthy people. We certainly see, I think, a very compelling case for a need to give additional vaccinations to people who are immunocompromised and that's why those that group has already been approved to receive a third dose.
But for the average person, first of all, no vaccine is a forcefield. The vaccine doesn't repel the virus from your body. The virus will likely infect your cells. And that's how your immune system knows something's afoot, and it should react, and what we can expect then, hopefully, is that your immune system will kick in. It may kick in fast enough that you never experienced any kind of symptoms, that it limits the infection to a small number of cells that you don’t develop symptoms. But it may not. And you may develop some symptoms. But the good news is that you have the other components of your immune system that we still think have long lasting memory about the virus based on what the vaccine told us, that those components of the immune system will kick in to help respond to this virus, so that you don't get nearly as sick as you would have if you hadn't been vaccinated, and to keep you out of the hospital and keep you from dying.
In my view, that is exactly what we need the vaccines to do. That is the most important thing. That's really what the vaccines were authorized to do. And that's what we need them for. I see no evidence whatsoever that they're not doing a good enough job for most people.
So why do we care? You know, [the question is] why don’t we say, let's just give everybody a third dose. Third dose, maybe it'll help, maybe it'll help ramp up their antibodies those, those, those fast tracking parts of the immune system, so they act even a little bit faster to keep the person who's infected from even developing, you know the lousy cold. If there were unlimited supplies of vaccines, I think it would probably be a straightforward, no brainer answer. Unfortunately there are not unlimited supplies of vaccine, and I just got some day that today from some colleagues from the Council on Foreign Relations that reminded me of the fact that four of the five billion doses of vaccines that have been allocated to date have been used by just 10 countries. Just 10 countries who, unsurprisingly are high income countries. So the prospect of boosters is really one of a global vaccine equity consideration because we just simply don't have enough vaccines to meet today's needs to get first doses, second doses into the arms of people who are even most vulnerable. And if we think about all of the places who are currently considering using boosters, if we added up all the doses that they could potentially use, that's an additional billion doses that will be third shots for people, as opposed to the fact that much, much, much of the world has not had even a first or second dose.
Africa, for instance, less than 2% of the entire continent of Africa has received a single dose of vaccine. So that's a moral problem, if you ask me, But even if you don't care about the morality of it, you should care about the pragmatism of it, which is that when you have huge populations that are unvaccinated, that is where we are most worried variants will arise. The countries that have lower vaccine coverage are the places that are more at risk for variants to emerge in part because they're not giving vaccines to the people who are most vulnerable, particularly the immunosuppressed who may be more likely to give rise to variants in the first place because their body has the bat virus for longer than some other patients.
So, if we're worried about variants -- if we want to stop hearing about Alpha, Delta, Beta, Gamma, Iota, I mean all of the Greek letters...I could go on, I don't know what happens when we run out of Greek letters, we'll start doubling them up -- then we should be really concerned about making sure we get more vaccines to others. Now you'll hear a lot of people talk about, well, we can make more and we should make more. Absolutely. But if we try to make more right now, it will be years before we do, and we don't frankly have that time. So it is actually a really concerning question as to how we in the United States can justify giving additional vaccines to people who may not need it to keep them out of the hospital or die when other parts of the world are literally dying for lack of access to any vaccines whatsoever.
This is a global pandemic, and the rest of the world continues to struggle. What I have seen over the course of this is that even countries that were very good at controlling COVID -- we heard for a long time of US was not doing well, but there are a number of countries that were doing really well, they've shut borders they did all this stuff -- even those countries are really struggling right now to get around Delta. Delta just spreads too fast for many of the measures that we've relied upon in the past. It really speaks to the importance of using vaccines to protect people. So anyway I will end there and am looking forward to the questions.
KU: Thank you. That gave us a really great overview. There was a question about the overall incidence of the virus and how early in pandemic, Africa was largely spared from the spread of COVID. Could you talk a little bit about that when it comes to vaccines?
JN: So, vaccines are the only way to protect countries now, but for along time, I mean, obviously countries are using other measures, but it's really hard. I think one of the most telling examples of this is Australia. Australia shut its borders, early, it had a very aggressive travel restrictions in terms of severely limiting who can return and even preventing citizens from returning, having hotel quarantine for two weeks. It helps them at various points, but now with Delta, I mean, we have had Sydney, the largest city in Australia, under lockdown for like months at this point. I mean that really just underscores how incredibly difficult it's going to be to return to normal until countries have vaccines, particularly to protect the people that were most worried about dying and the people who have the greatest level of exposure and that’s health care workers. I really worry about health care workers, because if we lose whole medical systems in countries that already have weak health systems, that will have generational impacts.
No country will be spared from this virus. It's really hard to compare numbers between countries, and I know that because I'm part of the team that runs the Johns Hopkins Coronavirus resource center, the map. One of the things that we have seen very clearly is that countries have very different approaches to finding cases, to testing for cases, to counting cases. And a big limitation is capacity. Many countries in Africa for instance, are only really testing travelers. Because travelers pay for tests. That means that the positives that they find among the travelers doesn't really represent what's happening in the country. My guess of what happened is that there are a number of countries, including probably places in Africa that shut down really early, and I think that bought them time. But they can't do that forever, and not when you have people who depend on being in the street to earn money. They can't do that forever.
And so unfortunately we've seen really devastating case increases in a number of countries, and probably more than what is reported based on the fact that there just isn't enough capacity to test everybody who comes into hospitals. They've done post mortem exams of bodies and have found a lot more COVID than anybody had thought. So, I think the most telling thing that we have seen is to look at something called excess deaths, which is just you look at the deaths and you compare the amount that occur in a period of time compared to what you would expect based on other years’ trends at that time. What we see is that the excess deaths show much more disease and death than has been reported, and I think this notion that this has been a problem of developed countries and not a problem of developing countries is completely false. In fact, some of the excess death data shows completely the opposite. It's a luxury to count your dead. I mean that's a really grotesque thing to say but that takes resources.
KU: I remember last summer when we had Dr. Peter Hotez on, and I think the statistic that he shared during his presentation around at the time was a 10-year horizon of when he thought we could have this kind of large scale global vaccination timeframe, really helping reach lower socioeconomic countries. What sort of timeline do you think about that?
JN: So we don't have 10 years. I mean, I think we barely have a year to have the most amount of impact. Viruses move really quickly. I won't say that vaccines won't continue to be important after a year, but if we want to have the most impact in terms of preventing unnecessary deaths, protecting health systems, we need to vaccinate within the next year. And that's why I get so frustrated when I see these vaccine production timelines that stretch into the years, because it'll be too little, too late. The vaccines will still continue to be important and I think that's when we have the conversation about boosting, and other things: once we have at least made sure that we have taken care of healthcare workers, and some of the people who are most likely to die, should they contract the virus in other countries. That’s the timeline that I think of in terms of variants.
Again, that's why we have to do more to reallocate. It's not just about bringing down all the numbers, but when you vaccinate more people in a country, it does slow the virus down. We see that in the US. The shape of the curves in highly vaccinated states in the US are much more gentle and gradual than in Florida where it's a skyscraper, or in Texas, and other places. And so, what vaccines also do is they buy countries more time to use the other measures to try to prevent people from becoming infected through other ways. But it's really urgent that we give them a leg up, that we give them some level of vaccinations so that they can not have their health systems overwhelmed so that people don't die not only from COVID that could have been otherwise treated and cured, versus, but, but other things. I mean we know if you go to a health system with a heart attack, and the health system is overwhelmed your likelihood of surviving is much lower. So, lots of reasons why it's pragmatically in our best interest to make sure other countries have access to vaccines, including but not limited to, helping reduce the likelihood of the emergence of variants. So far, I'm not completely worried about a variant emerging that completely overtakes, our vaccines in part because I do think we have good protection against a serious disease, and we've seen it so far, but the fact that that could happen is worrisome.
KU: Could you talk about the concept of vaccine induced selection?
JN: That’s basically disinformation. I think that came from maybe a misinterpretation of, of what happens with antibiotics, like you know you heard, if you don't take your antibiotics fully that you could select, or force, the bacteria to find a way around the antibiotics because it gets a hit but isn't killed fully. I think maybe there was a thought that the virus, now seeing a vaccinated population, can outwit it but we just haven't seen any evidence of that whatsoever. In fact we see evidence of the opposite, where the mutations are more likely to occur in places where spread remains unchecked. And again, you know in part, because I do really worry about immunocompromised people in particular.
KU: What are your thoughts on people who had COVID and have a form of natural immunity?
JN: I think it's highly likely that if you've had COVID, you have some level of protection. The challenge is, we don't know how much. It is possible it's better than we thought it is, and there was just a preprint that came out yesterday from Israel suggesting that people that had prior infection plus one dose of vaccine seem to have the most protection against reinfection as compared with people who had just two doses of vaccine, and people who had no vaccine. So I think it is likely that you get some protection.
We've also seen people who have had infection be reinfected, so it's possible that it's related to how severe of an initial infection you had and if you had a mild one perhaps you're not as protected as if you had a more severe one. What I take from this is, we shouldn't discount that infection causes any level of protection because it clearly does. It's just hard to figure out exactly how much. So for me, you know, getting at least one shot, if not two is like checking all the boxes and making sure you're covered. And there's really no downside to doing that. There is no worry that if you've had the infection and then you get vaccinated, that you're gonna have a worse reaction or that you're gonna have long COVID. I've heard a lot of concerns about that. If I hadn't had COVID, I would have not hesitated to go out and get two shots.
Now, we can argue as scientists, whether you need two shots or one or if you need it at all, but like, at this point, not fully knowing, it's kind of a gamble and let me tell you vaccines are the safer path to protection than infection because although a very like a young and healthy person, you know statistically you're going to survive your infection, it's hard to know as an individual, if you're in the statistical average, or if you're on the tails and the person who's going to die. So I'm all about thinking of how do we make our lives easier and kind of minimize the risks and worries and getting a vaccine is very clearly a way to do that.
KU: What do we know about the transmissibility of Delta? Will our current measures like masks and social distancing work?
JN: Delta is more transmissible. We've seen this now in data sets and I think there's a few reasons why that's happening. One is, it seems like if I were to be exposed, the time to which I would become contagious is a bit shorter than it was for earlier forms of the virus. So that just means that over a period of time I could potentially infect more people because I have more time to do that. We also know that people tend to have a higher viral load and more likely to being able to put virus out earlier in their illness. We’ve always known that people without symptoms can potentially spread it, but potentially it's a bit earlier, so that means that you've been more likely to spread it when you don't know it. And so that just makes it challenging. It might also be on balance, if you get infected, a longer time period in which you know you can transmit it. So we are seeing the growth of cases increasing more quickly than we thought with previous versions of the virus.
That's just how the virus works. But how we work to stop it has not changed. Vaccines are the thickest layer of protection. People who are vaccinated, even if they are to become infected, even if they are to develop symptoms, develop disease -- the period of time in which they would be contagious is shorter. And we also think that it cuts down the likelihood of having any symptoms and we certainly know that helps keep you out of the hospital so that's great. So vaccines are the thickest form of protection. Say you're a vaccinated person and you're wondering what you can do to further reduce your chances of getting Delta, all the things we've been doing since hearing about this virus: wearing masks, avoiding crowded indoor spaces, keeping your distance from people, trying to preferentially socialize with other vaccinated people. Try to avoid huge gatherings. Those are all the things that you can choose to do to further limit your likelihood of coming in contact with the virus.
KU: When you expect vaccines for younger populations?
JN: Yeah, so this is a really important question for me personally because I've got two kids who are too young to be vaccinated. So I'm in this boat that many other parents are in. So what we know about COVID and kids right now is, I would say, relatively unchanged, in the sense that when the overall number of cases increases, the childhood cases and kids also increase. And the same thing tracks for hospitalizations. So the more cases, you know, some fraction of that will result in hospitalizations.
There is some question as to whether Delta makes people sicker. I will tell you, I have not seen compelling data on that from clinicians who just are seeing patients. Some feel like the answer to that question is yes, others say no. The possibility of that makes people worry, understandably. The other thing that we see in the pediatric COVID case data is that pediatric cases tend to follow adult cases. So if adults get sick, they may spread to the kids in their lives. And so if you're a parent and you're wondering what you can do to protect your children who are too young to be vaccinated, the most important thing you can do is make sure that all adults in their lives are vaccinated. And that's why I think you're seeing school districts increasingly pushing to have teachers and staff in schools vaccinated because that's an important way to protect children in those settings.
Again, it's the same measures that we've been using: masks and distance and avoiding crowded indoor spaces. Since I have children in those circumstances, we’re all making risk benefit decisions and our level of risk tolerance is all a little bit different. I know for our family we prioritize risks that we think are beneficial to the health and development of our children, so for that reason, school in our minds is a very important thing. And if we have to minimize exposures and other settings to just account for the fact that now they're in school and they're going to be around more people than they were when they weren't in school, we choose to do that. I personally feel comfortable sending my children to school. It's not a zero-risk prospect but where I live in Maryland, the cases aren't as good as they had been earlier, but certainly not as bad as some other parts of the country. If I were in a state where the cases were surging and where a governor is restricting any level of mitigation in the classroom, I would be a lot more nervous.
KU: Will the full FDA authorization of the Pfizer vaccine help decrease vaccine hesitancy?
JN: I've heard from a lot of people who are not yet convinced about vaccines. One of the things that they were waiting for was FDA approval of the vaccines. Sometimes they were waiting for themselves but probably more frequently I heard it from parents who were themselves vaccinated, but were waiting for it for their children. The thing I told parents in this situation is that, I understand that, you know that the idea that there's like another level of check. I can see why that is reassuring. I just didn't fundamentally expect the facts to change by the time approval came, such that I didn't really see the benefit of their waiting. I just didn't think it was ready to change that much. There's a difference for sure and one of the differences that full approval is for forever. And part of what the negotiations were about was how long it could be stored in doctors offices and the refrigerators that they have there. There was a lot of additional review. I won't say that there's no difference because there is. I just didn't think that, for the things that people cared about -- is this going to be safer for me right now -- that the facts were going to change.
I hope approval makes people more comfortable. It should. I mean, I think there's been a really rigorous evaluation. One of the reasons why we don't yet have vaccines for under 12, I mean the FDA just went back to Pfizer and said expand your study and include more children to look for rare events. I have a lot of colleagues who are pushing for a faster decision on vaccines. I'm not necessarily. I mean, I would love to have a vaccine for my children because it would just eliminate some additional worries. But I think it's really important for parents in particular to understand that the process is happening in an evidence based manner. It's not being rushed in any way. Yes, we're in emergency. Yes, obviously we want children to get vaccinated. But the risk benefit calculation for children is different than it is for adults. And so, there is going to be a higher standard of scrutiny for pediatric vaccines than there will be for adults just because the likelihood of severe outcomes is much smaller.
Many employers were waiting for FDA approval before they were going to mandate vaccines, including the Department of Defense, which is now already mandating it. And think that these vaccine mandates that we're seeing from employers -- I mean they just keep coming and I think that that's going to change who's vaccinated and who's not.
KU: Do you have a timeline for a vaccine for children?
JN: What I hear is probably not before the end of the calendar year. I think the hope was that they would have data by September and that it'd be closer to late fall, but it’s probably not till the end of the year. I do also have to say --I don't expect this to happen -- but it is possible that they won't approve it. I have no evidence to say they're not going to approve it, but I feel like so many people are just kind of biding time until it happens. I hope we have the vaccines, but, you know, the approval process is gonna find what it finds. And like I said, the calculation was not quite as straightforward for very young children as it is for even teens. Teen,s I think there's a much more compelling risk benefit calculation. Not that there isn't for children. I think we have to just continue to do what we're going to do and make decisions for our children, hoping that we're going to have a vaccine, but also not completely banking on it. I don't want to leave people with the impression that we're not going to have a vaccine. I just want to say: let the science work its way out and not push it.
KU: Let’s talk about the terminology around breakthrough COVID cases.
JN: I think we have to be very clear if we're talking about infections, or if we're talking about disease. Again, the virus is what infects you. And then depending on how your body reacts, you may get the disease. The disease may involve symptoms. I think we probably should not talk about breakthrough infections. That suggests that we expected vaccines to prevent infection. If anything, we hoped that they would prevent productive infections that go on to develop disease. But I don't see any reason why we should have ever expected vaccines to prevent infection because, again, the way vaccines work is they train your immune system to respond when your cells are infected.
The question is, how quickly can it do that before you get any level of disease? We're seeing now more people who are vaccinated developing disease, though, go mild. Generally mild. So I think when you hear things like breakthrough infections are rare, that's wrong language and we probably shouldn't be saying that. I think we should be saying breakthrough disease. It’s still pretty rare. Not as rare as it once was a few months ago. Breakthrough severe disease, very rare. Exceedingly rare. Breakthrough hospitalizations, it's incredibly rare. That what CDC is tracking and we definitely have the data on that to know that that's not happening frequently and when it does it's often people who have some level of underlying condition.
I do think that we're all going to get infected with this virus at some point in our lifetime. So for people who are on the fence about getting vaccinated, they can like they could just kind of N-95 mask and hole up until the virus goes away, I don't see that happening. I do think that through increased vaccinations and defanging the virus and taking off the table its ability to put people in the hospital, and to kill them, our relationship to the virus will change. We will probably at some point stop tracking individual infections. People who have virus in their nose, but are otherwise not sick. I don't see that as being particularly relevant in the long term right now, given that we're very actively trying to control the spread of disease. The spread of this virus that's still resulting in high levels of disease. We of course have to track these things. But I think at some point, our relationship with the virus is going to change.
The current recommendations are that fully vaccinated people who have no symptoms, and no particular reason to think that they have COVID because they're not a contact of a case, shouldn't be tested. And part of it is that if you do get tested, and you test positive, it's really actually hard to interpret. Again, the way that vaccines work is that they train your immune system to go after the virus. So it's very possible that that positive test is catching at that moment when your immune system is doing exactly what the vaccine taught it to do and is going after the few cells that have the virus, and it's destroying it. That virus may not even be capable of infecting other people. It can, but we don't know. That test doesn't tell us.
Certainly if you have symptoms it is important to get tested so that you know, so that you can take precautions, so that even though you probably have less of a likelihood overall over the duration of your illness to spread to others, there is a period of time in particular where you may be more likely to do that. So it's good to know so you can protect yourself. And certainly if you've been exposed to a case, think about potentially getting tested although when and when exactly you do that, is a little bit trickier. But those are the most compelling reasons. But when you hear of people who are vaccinated who have no symptoms but are part of a business or a sports team in which they are regularly being tested, and you're hearing about those positive, those positives alone don't necessarily make me worry. If those people went on to become, ill then that's a different story. If they become quite ill, then that's when I really get concerned. But so far I haven't seen that.
KU: Are there any advantages or disadvantages of either going to a COVID testing center versus using a rapid test?
JN: So it's really operational at this point. I was in a similar boat. My daughter had a exposure at a daycare, and I needed to get her tested. So the PCR tests are generally thought of as being more sensitive so they're more likely to find viral genetic material in your nose. The additional time those take to find it compared to other types of tests may not be as important from a public health standpoint, but nonetheless, because they may detect it earlier, or even later in your illness, then the rapid test that you could potentially buy.
The downsides of PCR are that they take time to get those test results. And in the case of my having to go and get my daughter tested, I found out about her daycare exposure six days after her last exposure to the infected teacher. So, they say between five and seven days, you should get tested and so I wanted to get a PTR test. I probably shouldn't have even bothered because after we got our swab – it was incredibly hard to find a place that would do it on that day, and I think that's a common story. When we did find a place, they told us that it would be two to five days before we got our test results back, and it wound up being, I think, maybe four days.
So the challenge is that the test only tells you what you were that day. If you get your results four days later, you don't know if those results are still relevant. I think there's some real advantages for the rapid tests. Sure, they may not find smaller amounts of virus in your nose, or the very beginning or the very end of infection, but you can repeat them and you can get the test results in 15 minutes. The downside is that you have to pay for the ones in pharmacies, and it's not inexpensive. The one that I purchased that we ultimately wound up using was $25 for two tests. I really valued having that, but I know for a lot of people, you're gonna think about how many times you're going to use those tests. But there may be circumstances in which you need to do that. You need to get timely test results. So I say whichever circumstances work for you based on your condition, then that's helpful.
A downside from a public health perspective is that those test results don't usually get reported. So if everybody's using those, we wouldn't be counting those cases. I have long been worried about that. I'm still worried about it, as someone who is tracking the reported numbers every day. I'm so worried about it. But if the alternative is that you don't get test results in a timely enough manner to take the public health action, which is what testing is supposed to do in the first place, I would much rather people get the test and stay home when they're supposed to than pushing for a test that is just providing test results too late for people to act within that small window of time they have.
KU: Any studies underway to investigate the impacts of mixing and matching different vaccines?
JN: There are, and I think they're encouraging, so far, encouraging from a safety perspective, but also potentially in efficacy and that's one of the questions that people are also asking about: if we need third doses, does it make sense to use the same vaccine that we've had, or wait a bit and maybe boost with something else to train our immune system in a new way. I think there's some data that suggests that the answer to that maybe that's better and so that's why I think if you hear of people sort of pushing back on boosters it’s because we haven't fully figured out if it’s necessary, but also how to do it.
That's said, and maybe this will be my ending comment, is just I sketched out global concerns about the need to share vaccines with the rest of the world. And you know, these scientific debates can be really overwhelming for individuals. And you know I will say even earlier, when we authorized vaccines for teens, I was concerned that we were one of the first countries, one of the only countries to use vaccines in a lower risk population when, again, there are very high risk people dying across the world for lack of access. Well, you can have these debates about policy, which is really what it is and what we as a nation should be doing in terms of our policies around vaccines. That’s not on individuals. If your doctor says get the third dose, your refusing it is not going to change the world circumstances. We can push for our government to do different things but as individuals, you know, if your clinician is recommending something for you, listen to your clinician, and you're not going to solve the world's problems in that office.
KU: Thank you very much, Dr. Nuzzo.
The Institute for Science & Policy is committed to publishing diverse perspectives in order to advance civil discourse and productive dialogue. Views expressed by contributors do not necessarily reflect those of the Institute, the Denver Museum of Nature & Science, or its affiliates.