Episode 1 – Is COVID-19 Immunity Possible?


Researchers are discovering that COVID-19 antibodies can vanish in as little as two months after infection. What does that mean for those who’ve recovered and efforts to find a vaccine? A discussion with virologist Bob Garry and immunologist James McLachlan about what we’ve learned about antibodies and why the innate immune system may be more important in fighting off the virus than first realized.

Transcript ▾

Bob Garry, James McLachlan, Carolyn Scofield


Carolyn Scofield  00:04
The COVID-19 pandemic has been going on for seven months now, but there's still so much we don't know about the virus.

James McLachlan  00:11
My optimism lies in the smart folks who are doing this work. And I think, I think we'll get there. It’s just gonna take a little longer than we'd like.

Carolyn Scofield  00:18
James McLachlan and Bob Garry are both researching COVID-19 at Tulane University School of Medicine. On Good Authority checks in with both of these experts. My name is Carolyn Scofield, and I work with Tulane Communications. Welcome to our new podcast. First, let's start with Dr. Garry. He's a professor of microbiology and immunology and has been studying emerging viruses for years from Lassa fever to Zika. His attention is now on COVID-19. Dr. Garry, welcome to On Good Authority. First, it's been seven months really since the pandemic started, how are you feeling right now?

Bob Garry  00:54
Well, I'm feeling that we still have a long way to go to get out of this. And I think that, you know, we're going to need some good leadership, to bring people around to the idea that we need to really do some of these mitigations to keep this outbreak from rebounding again, and then rebounding again. And so, right now, we're basically putting a lot of hope on vaccines and some other things that are likely to be many, many months off. So, we're still in it for kind of a long haul, I think.

Carolyn Scofield  01:31
How close do you think we are to getting a vaccine and getting that out to everyone?

Bob Garry  01:37
That's going to be quite some time, actually. I mean, we'll know some initial things about many of the candidates, you know, over the next coming months. I mean, I'm not sure that, you know, the FDA will have enough information on any of them to approve, you know, by November or first the year. That's going to take, that's still going to take some luck, and that's really up in the air. I mean, some of the trials may be over, but it takes some time to analyze that data and to look, you know, look at the safety and efficacy. So, people are working as fast as I can on this, obviously, because of the situation that we're in, but getting a vaccine approved, you know, in the next couple months, it could happen. But the next step of distributing it to the people that really need it, that is definitely going to take, you know, many more months after that. I believe some of the estimates, some of the experts like Dr. Fauci have said, if we're, you know, distributing vaccine by the middle of next year to the folks that really need it, we'll be doing quite well.

Carolyn Scofield  02:38
If a person gets an antibody test, and it's, it shows that they have the antibodies, does that mean they're okay to return to work and life, and don't have to follow all the same social protocols that everybody else is following?

Bob Garry  02:54
I mean, if you've been infected with, you know, the SARS-CoV-2, if you're a COVID-19 survivor, and you've made the antibodies, you're likely protected from that virus, at least for several months. I mean, we don't know the duration of the immune response. But it's, it's more than likely that, you know, you've got several months of protection built in there. I mean, hopefully it'll be longer than that. Hopefully, it'll be six months, even a couple of years. But right now, we just don't have that, you know, enough information to say with confidence that yeah, that person can, you know, be totally free, they can get a, you know, a green armband, and go and do whatever they want, because they're a COVID survivor, and they're not going to be infectious and passed on to other people. We just don't have the competence that that's gonna apply to enough people yet to be able to do something like that.

Carolyn Scofield  03:46
A lot of people have mentioned the term herd immunity, and we even heard it phrased recently as herd mentality. What exactly does that mean?

Bob Garry  03:54
Well, yeah, it's herd immunity is what the term that should have been used there in that case. And that's, that's what a lot of people have been talking about for quite some time. In fact, it's national policy in Sweden. And, you know, Sweden's had a mixed outcome with sort of just, you know, letting the virus spread through their population. In fact, up until a few minutes ago, they had the highest, some of the highest, rates of infection and deaths in any country in Europe. Now, those have come down in Sweden over past few weeks or so. But the estimate is, is if we try to herd immunity, just let the virus go and undo all these mitigation effects and you know, just open up the economy and everybody to life as usual that, yeah, we can achieve herd immunity. But it will cause at least a million deaths and as many as 6 million, so I mean, I’m just one that thinks that's too big a price to pay for, you know, for this short-term economic benefit.

Carolyn Scofield  05:01
So, hearing all of that, and we're still months out from any kind of vaccine, and they're still trying to figure out what the best treatments are. It all sounds kind of terrifying in a way.

Bob Garry  05:08
You know, I have to admit that there were some nights that I lost some sleep over this virus, because it has some features in its genome that that other viruses have that have gone and caused pandemic diseases. There's something in the spike protein in the virus called the furin cleavage site, which makes the virus, you know, pretty pathogenic, able to spread through the body and cause a lot of damage. And when I saw that SARS-CoV-2 had this, some very potent influenza viruses have this, I knew that, you know, this was going to be a threat.

Carolyn Scofield  05:42
It almost seems like the SARS-CoV-2 virus preys on all of our health and social vulnerabilities.

Bob Garry  05:48
Yeah, if you wanted a virus that was gonna disrupt our society, then give us one that's going to keep us from going to football games and going to bars and things like that. That's going to have a big impact on a lot of people's quality of life. And certainly, we're seeing that with SARS-CoV-2.

Carolyn Scofield  06:04
I read a study recently that found wearing a mask may not only stop a person from spreading the virus, but it could also protect them from inhaling as much of the virus, if say somebody around them is infected.

Bob Garry  06:18
Yeah, that's, that's a pretty consistent finding in virality, that the virus load does make a difference. You know, not always and everybody responds differently to, you know, different viruses. But just in general terms, if you are exposed to a low amount of virus, it takes a little longer for the virus to replicate and to build up numbers of virus particles in your body, and  that also, you know, gives your body's defenses time to come into play and keep that virus slowed down. So, less virus, less disease. The mask, you know, not perfect, I mean, an N95 respirator that, you know, that we wear in the biosafety-level labs and that the nurses and doctors wear when they are treating COVID-19 patients will do a better job of blocking the virus from getting into your lungs. But you know, even just the cloth masks, the surgical masks that you can buy and purchase and wear now will knock that virus load down, and hopefully have an impact on your disease course if you do get infected.

Carolyn Scofield  07:28
We go now to James McLachlan. He's an associate professor of immunology at Tulane School of Medicine. Dr. McLachlan, let's talk about immunity. How long do you think it lasts?

James McLachlan  07:37
So the 1918 influenza pandemic, which you know, happened in 1918. There was a study probably 10 years ago, where scientists looked for survivors of that pandemic, who were I think, at the time four or five years old, and had been infected with the 1918 influenza. And they found antibodies that recognize and were neutralizing so basically protected, potentially against the 1918 influenza, almost 100 years later. So, immunity in certain viruses can last almost your whole life, and immunity to other things can last less long. We don't know that the infection with COVID-19, how long the immunity to that particular virus will last. There's some recent data, very recent, from a former colleague of mine, actually, who's at University of Washington, Marion Pepper, who's done some really outstanding work, where she showed at least three months after infection, that you can find antibodies that are neutralizing. So, you know, these molecules that basically prevent the virus from binding to cells, it can block the entry of the virus three months after infection, even in people with mild or no symptoms. So that's certainly encouraging that we may have, we may have immunity that can last three months, but we’ve only known about this virus for three or four months. So, we're sort of in this weird limbo phase, particularly for immunologists, where we can't really look far out because we don't have far out.

Carolyn Scofield  09:00
Do the current COVID-19 antibody tests give you a complete answer about potential immunity?

James McLachlan  09:06
There's actually one other cool thing, I think, that's probably worth thinking about. So there, like I said, there's the antibodies. And the most important probably, I think aspect of this, and that's the test that's easiest. There's another part of your immune system that are called T cells, then these T cells are what help make better antibodies, so they don't actually make the antibodies, but they help the immune system make better antibodies. And one of the things that's been pretty interesting in the news, and you may have read about, there may be, so T cells also, like antibodies, very specifically recognize different pathogenic organisms, viruses and bacteria. And so, there's some evidence that there are already T cells in a lot of people circulating around that already recognize COVID-19 and are already primed to respond to COVID-19. So, they basically remember COVID-19, which is weird because it's a novel coronavirus, and it turns out they probably are specific, and they recognize common cold coronaviruses. And it may offer some cross protection depending on how much of these cells you have in your body. And so, people are really, really interested in investigating whether or not that kind of preexisting immunity based on getting the common cold is actually good at helping protect you against COVID-19. Which I think is really, really cool and kind of surprised a lot of immunologists that this kind of cross-reactivity was occurring between these two different kinds of viruses. So that would be nice to know if that's true. And in fact, Dr. Pepper’s paper shows that there may be even antibody-producing cells that also have preexisting cross protection against COVID-19, probably also from cold, your common cold coronaviruses. So, you know, I'm not suggesting go out and get the cold for fun. But, you know, maybe if you've had it in the past, it protects you.

Carolyn Scofield  10:56
With so many questions about the virus and not enough answers, are you optimistic that we'll get this pandemic under control?

James McLachlan  11:04
I'll tell you, where my optimism lies mostly is with the scientists who are studying the disease, studying the infection. The immunologists who are trying to understand how the immunology, the immune system will respond to the infection. And really, I think the folks who are developing these vaccines, I have real faith in those groups of people to come up with therapeutics. You know, things that can prevent or, or help cure infection, or at least slow down infection, and in the folks who are making vaccines who I think are really, really clever people. And to be fair, I'd like to consider myself among them. So, you know, I don’t know if you know, Dr. Lisa Morici and I just got a fast, COVID fast grant to start looking at developing novel vaccines against COVID. So, we're all, I think our enthusiasm and our optimism is in the fact that there's a remarkable number of smart people working as hard as they can on this and trying to figure this out as quickly as possible.

Carolyn Scofield  12:10
Dr. Garry also finds reasons to be optimistic.

Bob Garry  12:13
Well, of course, yeah, we are going to get through this. And, you know, there will be a vaccine. We will one way or the other achieve that herd immunity. Is it going to be in the next year? Is it going to take us longer than that? One way or the other. Hopefully, with a vaccine, yeah, this, this virus will gradually become less of a factor because there'll be more and more people that have been exposed, and more and more people who've been immune. So what the question is, is, you know, are we gonna have SARS-CoV-2 forever? And, you know, a lot of people think that's very likely, that it will become an endemic virus, like the seasonal coronaviruses that cause about 30 percent of, you know, winter colds in any given year. And that's, you know, that's not a, you know, really pleasant thought, because this virus has, as we've been discussing, you know, a pretty high mortality in, in people that either have predisposing conditions, like hypertension or diabetes, obesity, and in the elderly. So people that are, you know, mostly over 80. So, you know, the thought that we, you know, have a virus like this that could cause such a serious problem in those populations, that means we really do need to focus on getting a vaccine that's, that's, that's effective and get that vaccine at least in those populations. Otherwise, you know, we're going to have a virus that's going to just keep coming back at us, and then now the other thing we need to do is to be better prepared for the next virus, the next pandemic. I mean this, we say it with every outbreak. We said it with the Zika outbreak. We said it with the West African Ebola outbreak, that you know, that that killed 11,000 people, and we're saying it again with SARS-CoV-2. This time, we really need to, to get our act together, to learn how to make diagnostics quicker and better. To learn how to make vaccines quicker and better and to be better prepared for that next outbreak because it's going to come. There's going to be a SARS-3, there's going to be a SARS-4, and there's going to be other viruses that are going to emerge too that we kind of have an idea what some of might be, but, you know, we need to get better prepared for all those eventualities.

Carolyn Scofield  14:36
Until rapid tests and a vaccine are available for the current virus threat, both Garry and McLachlan say everyone should continue following the best guidance from experts. That means wear a mask in public settings, stay six feet away from others and keep up with that frequent hand washing. Thank you for listening to our new podcast, On Good Authority, and catch our newest episode by subscribing on your favorite podcast app. For more information on our show, visit tulane.edu/on-good-authority.

Host: Carolyn Scofield
Editor: Carolyn Scofield
Producers: Marianna Boyd and Audrey Watford
Production team: Marianna Boyd, Keith Brannon, Will Burdette, Faith Dawson, Libby Eckhardt, Aryanna Gamble, Carolyn Scofield, Mike Strecker and Audrey Watford

Listen to other episodes of On Good Authority.