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Podcast: COVID-19 vaccines around the corner

This episode of 'Show Me the Science' reports on progress toward a vaccine and how to stay safe before vaccines become widely available

December 9, 2020

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A new episode of our podcast, “Show Me the Science,” has been posted. At present, these podcast episodes are highlighting research and patient care on the Washington University Medical Campus as our scientists and clinicians confront the COVID-19 pandemic.

Drug companies are reporting eye-popping success rates in clinical trials of their vaccines to prevent COVID-19. It’s possible the first people in the U.S. could begin getting shots before the end of the year. In this episode, we’ll hear about the amazing pace of vaccine development, as well as Washington University’s role in vaccine research, from infectious diseases specialist Rachel Presti, MD, PhD, an associate professor of medicine and medical director of Washington University’s Infectious Diseases Clinical Research Unit. Presti discusses how soon most of us can expect to get a vaccine and how safe those shots are likely to be. In addition, we visit again with Matifadza Hlatshwayo Davis, MD, a clinical instructor of medicine in the Division of Infectious Diseases. She discusses how COVID-19 and the flu might interact as the pandemic continues during flu season. Hlatshwayo Davis believes it’s important for everyone to get a flu shot, and she and Presti both think that if we can double down on use of masks, hand-washing and social distancing, it will limit the spread of COVID-19 while also cutting down on the number of flu cases we will see.

The podcast, “Show Me the Science,” is produced by the Office of Medical Public Affairs at Washington University School of Medicine in St. Louis.



Jim Dryden (host): Hello, and welcome to “Show Me the Science,” conversations about science and health with the people of Washington University School of Medicine in St. Louis, Missouri, the Show-Me state. As we continue to look at Washington University’s response to the COVID-19 pandemic, we focus in this episode on vaccines.

Rachel Presti, MD, PhD: I think it’s really, really exciting. The numbers that they were reporting are really remarkable, really kind of best-case scenario of what we were thinking we might get. So I think it’s very promising.

Dryden: That’s infectious diseases specialist Rachel Presti. She’s running the vaccine trials at Washington University School of Medicine, and she says with a few vaccines reporting early successes at much higher rates than anticipated, and with more reports expected soon, we could see some people in the United States vaccinated against the SARS-CoV-2 virus before the end of the year. But even with the good news, most of us won’t have the opportunity to be vaccinated for several more months. So infectious diseases specialist Mati Hlatshwayo Davis says it’s important that we double down in our efforts to protect ourselves over the next couple of months. Part of that, she says, involves protecting ourselves against other viruses that circulate at this time of year, particularly influenza.

Matifadza Hlatshwayo Davis, MD: If we don’t have a really good and successful flu campaign, and we have a situation where our hospitals are overwhelmed with sick people from flu, from the myriad of other respiratory viruses out there on top of the fact that we have people still getting sick from coronavirus, we will again find ourselves in a situation where our resources are stretched.

Dryden: Flu shots have been available for several weeks. For coronavirus vaccination, not quite yet. But Pfizer, then Moderna, then AstraZeneca, all reported that their vaccines appeared to work. All reported success rates much higher than had been expected. And according to Rachel Presti, that means some people could start getting vaccinated in a few weeks.

Presti: They were talking actually about having vaccines available maybe in mid- to late December. Those would be small numbers, and it would probably be the Pfizer and the Moderna vaccines. They would probably be mainly for healthcare workers who are at high-risk and other folks who were essential workers who are at high risk of infection.

Dryden: A lot of people had expected these first COVID vaccines would be closer to 50 or 60 percent effective, and that would have been considered good. So how big a deal is it that these early vaccines keep reporting success rates so much higher than that?

Presti: I think it’s really, really exciting. When you still have small numbers, you always worry about there being some small statistical kind of issue. But the numbers that they were reporting are really remarkable, really kind of best-case scenario of what we were thinking we might get. So I think it’s very promising.

Dryden: How do these studies determine that the shot is working, rather than that the volunteers just didn’t get sick?

Presti: Obviously, there are a whole lot of people who got vaccinated, and there were whole lot of people who didn’t get vaccinated, who never got exposed in that timeframe. So it’s important to continue to follow people. But a 90% efficacy means those numbers don’t happen very often by accident.

Dryden: Now, the news about the vaccines was encouraging. But that Pfizer vaccine, and I think the Moderna vaccine as well, require some very specialized refrigeration. I guess Moderna doesn’t have to be quite as cold. But people also need to get two doses of each of those shots to work. And I wonder if that makes it important to keep looking for other vaccines that might be easier to store, easier to get patients to comply with.

Presti: Right. I mean, I think we’re going to need multiple different vaccines because we’re going to need to be able to vaccinate the entire population of the world, really, to address this. This virus has really gone worldwide. And the Pfizer vaccine is going to require ultradeep cold storage, and that is just not something that is easy to do worldwide. It can be done in the US, but even in the US that is somewhat difficult. The Moderna vaccine requires freezing and sort of the normal freezer temperature, but that still is a little bit difficult. And you have to know that your freezers are not failing, you have to have access to electricity to keep things cold. Our hope is with the newer vaccines— AstraZeneca actually can be stored at sort of refrigerator temperatures for quite some time. The closer we can get to a vaccine that doesn’t require cold storage throughout its journey from the pharmaceutical company that’s manufacturing it to your arm, eventually, the easier this is going to be. And then, the other thing is the number of doses. So ideally, a vaccine that is a single dose that doesn’t require cold storage would be the best potential vaccine. But we also need one fast. So it’s great to have these vaccines available and know that they work because we can get started protecting some of the people who are most vulnerable.

Dryden: How long do the drug companies have to wait in order to demonstrate safety?

Presti: The FDA set out rules. They want at least two months of follow-up on all their participants after they get both doses of the vaccine.

Dryden: There’s been a lot of talk about whether the natural immune response persists in people who have had COVID-19, or whether they can get re-infected. Now, if they only test this vaccine for a few months, do we really know how long the protection lasts? Or do you expect this will be like a flu shot that we have to get every year at some point?

Presti: So I think we don’t know. I think that’s part of the reason why almost all of these studies are designed to last for at least two years. And so, hopefully, we’ll have enough people who stay on the study arm. We would continue to follow them. And that way, we can see how long does the vaccine last. How long does the antibody response last? What is it that you need? And then, we’re getting a lot of blood so that we can see how long that does last. Most of these vaccines are sort of targeting the same kind of immune response. So they’re using different strategies, but they’re all targeting the same protein — that spike protein — on the virus. If that works in one vaccine, it’s very likely that it’ll work in another.

Dryden: A year ago, we had not heard of SARS-CoV-2. And now, there’s a vaccine. That’s far and away the fastest vaccine development in the history of vaccines, I’m guessing. And I wonder if there’s any fear that in moving so fast, some corners might have been cut?

Presti: We tried not to. There’s always things that might happen that you find out about. And when you move this far this fast, there’s a temptation to say, “Oh, I think that’s still okay.” But in reality, I’ve been very impressed. Both AstraZeneca and Janssen paused their studies. With all the pressure on these companies and the researchers doing the studies to get an answer fast, on the basis of one person getting sick with an unusual illness that could have potentially been related to the vaccine, they stopped the study. And they waited, and they evaluated, and they had multiple scientists look at the data. And so, those kind of safety corners are not being cut. We’re hoping that if there are side effects that you’ll see them early. And we’re hoping that the fact that we are enrolling tens of thousands of people into these studies— these are huge vaccine trials, much bigger than we’ve done in past. So we’re hoping that we will have that information because we’ve done it in more people, even if we tried to do it as quickly as possible.

Dryden: Nonetheless, there is lots of suspicion of other vaccines too. Some people refuse to have their kids vaccinated. Do you expect that even after a vaccine is approved, we may still get COVID outbreaks because some people are going to refuse to get this vaccination?

Presti: I think that’s possible. The thought is that this might become one of those seasonal viruses, and we may see it come through. I think there’s still questions about whether or not we could come up with a better treatment or a better vaccine, that would target coronaviruses more in general. We’ve now seen these outbreaks of SARS and MERS, and now SARS-CoV-2. It was easier to come up with a COVID-19 vaccine because of all the work that was done trying to make a SARS and a MERS vaccine that never got fully developed because those viruses went away. So you don’t think this one is going to go away. We think it’ll probably wind up circulating to some extent, and the hope is that we’ll have enough immunity to it that we won’t see these kind of huge outbreaks that we’re seeing right now.

Dryden: With those other viruses, I mean, one of the reasons they went away was that there was more than just a waiting for a vaccine, there were lots of public health measures that were taken. So I’m guessing that while we’re all waiting and hoping that the news about vaccines continues to be good, we still need to do the things that we’ve needed to do from the beginning.

Presti: Oh, absolutely. And right now, we’re looking at really scary numbers. We’re seeing the hospitals filling up. This is the nightmare scenario that people were worried about back in March. New York especially, there were certain areas of New York that just saw huge numbers, and the rest of the country didn’t experience that. I think it’s always a little hard to prepare for something that you don’t have direct experience with. And yet, it’s so critically important because if we run out of ICU beds, if we run out of places in the hospital to take care of people, then people are going to die because we can’t do what we need to do.

Dryden: There are vaccine candidates that are being tested at Washington University School of Medicine. Is it still possible for people to volunteer?

Presti: They’re still ongoing. It’s still possible to volunteer. We have had tremendous outpouring, great community support for the vaccine studies. But each of the vaccine studies, we’re expecting that we may be doing more, and each of the vaccine studies have slightly different eligibility criteria, slightly different people they’re looking for. And so, yeah, if people are interested, I can’t promise that I can get you on the vaccine study tomorrow, but we are still looking for people. Yeah.

Dryden: Until then, I guess masks, handwashing, social distancing, until, and even beyond, the time that some of us get vaccinated.

Presti: Right. So I mean, the vaccines aren’t going to work instantaneously. You need to get that immune response, and that usually takes about three weeks. So we want to make sure that you can’t rip your mask off and stop washing your hands the day after you get the vaccine. The other thing is what we’ve noticed with handwashing and wearing masks is, we’re not seeing a lot of flu right now. And when we shut things down in March, we not only did a decent job trying to flatten the coronavirus curve, but we saw other respiratory viral infections just plummet. So these work. It works as a way of keeping yourself healthy and safe, and to some extent maybe should be something that we think about doing a little bit more. Not shutting the economy down, not shutting the schools down; but think about washing your hands, and think about wearing a mask in these respiratory viruses.

Dryden: Presti says even if it does keep those vaccinated from getting sick, we won’t know right away whether the vaccine also prevents those who get the shot from spreading the infection to others who haven’t yet been vaccinated. So even after people are vaccinated, Presti says it’s important for them to remain vigilant with masks, distancing, and handwashing; still our best strategies for fighting COVID-19. Those practices also are likely to help protect against flu. Mati Hlatshwayo Davis, also an infectious diseases specialist, says because COVID-19 is so new, it’s not yet clear how the novel coronavirus and influenza will affect one another.

Hlatshwayo Davis: We don’t know what flu and coronavirus are going to do together. That is a sort of ‘time will tell’. What is important, and what we do know, is that flu on its own carries with it a high degree of morbidity and mortality, right? People can get very sick, and people can die. We know that we need to protect ourselves from flu. We know what we’re dealing with with coronavirus. And so it’s obvious that to have both of them not at a place of being well-controlled will be difficult, and, quite honestly, devastating if we don’t get ahead of it. The level that a lot of us in the public health sector are most concerned about is not so much on the individual level as much as how this will impact our hospital systems. If we don’t have a really good and successful flu campaign where people get their vaccines early and are willing to actually get them, and we have a situation where our hospitals are overwhelmed with sick people from flu, from the myriad of other respiratory viruses out there, on top of the fact that we have people still getting sick from coronavirus, we will again find ourselves in a situation where our resources are stretched. Where we don’t have enough beds for those who critically need them. Where we don’t have enough ICU space and ventilators for those that critically need them. And where we possibly then run into issues around supply. So it’s critically important that we try to prevent what we know we can prevent. And our prevention strategies for flu are: get your flu vaccine and continue the same preventative strategies around COVID that will also help with flu and other respiratory viruses. Masking up is key. Masking up is the number one thing that I think people need to really, really get on board with. Washing hands with soap and water; where that’s not available, with hand sanitizer with at least 60% alcohol. Social distancing at least six feet apart if you’re in public, right? So avoiding large gatherings, particularly indoors. And those things will go such a long way to making sure that we keep the case numbers down from both influenza and coronavirus.

Dryden: Some of that was sort of at a macro level, though. At a micro level, I wake up, and I feel sick. Then what? I mean, I assume a phone call to the doctor is in order. We don’t want to just show up at a doctor’s office. But should we isolate? Should we get tested? How does a person make that sort of a determination?

Hlatshwayo Davis: I think it’s critically important not to play your own doctor as much as possible. So for anyone who has access to a primary care physician, I think that should be your first call. A lot of the symptoms that we see with coronavirus are very similar to what we see with flu and other respiratory viruses. There are some differences. For the most part, we see with coronavirus, it’s not this sudden attack where you suddenly go down; whereas, with flu, you can oftentimes feel like you’re hit by a truck almost immediately. But every disease does not follow the rulebooks. They’re just variations around common themes. And so, rather than try to make assumptions or— I mean, one thing I would say is if you wake up with symptoms, whatever they may be, whether it’s a fever, cough, trouble breathing, difficulty smelling, loss of taste, and other type of symptoms, the first determination is, “How sick do you feel? Are you comfortable enough to still be at home?” And if so, the first call really should be to your primary care physician. But if you’re in a position where there is concern about how stable you can be at home — you’re having trouble catching your breath; you feel really, really bad — then you have to go to an emergency room. I think the biggest message here is there are many similarities between these viruses, so it’s important to get testing wherever possible, and that you cannot be your own physician. So to that extent, try to engage the healthcare system as much as possible. Other resources that I think are important for people who need help who may not have access to a primary-care physician or who have other barriers that prevent them from being able to access the health-care system, whether it be they don’t have transport, they have trouble paying bills, that they have trouble getting food for their families, are number one, the CDC’s website is amazing. And it breaks down information on all of these topics we’ve been talking today very clearly and succinctly. But our county and city Departments of Health have incredible websites with all the sort of resources and numbers you can call to ask questions if you’re struggling. So I would definitely direct people to engage in those resources.

Dryden: Should we have little oximeters at home? A thing that we can put on our fingers so that if we feel bad, we can get a quick read on what our blood oxygen level might be?

Hlatshwayo Davis: That’s an excellent question. I’ll tell you a story first by way of example. When I was pregnant with our first child, I said to my husband, “Babe, I found a home ultrasound on Amazon. I think I’m going to get one.” And he looked at me, and he said, “Woman, absolutely not. You? With an ultrasound, with all of your anxiety and fears around the baby? What happens if you don’t know how to use it, and you don’t hear a heartbeat one day?” So I say that to say, I’m very wary of people arming themselves with tools that they may not be equipped to understand or know how to operate fully. So I think those types of contraptions, while I absolutely advocate for them, should be done under the observation and guidance of a health-care professional. My home hospital, Barnes-Jewish Hospital in Washington University School of Medicine, we have a home-monitoring program. So if you get diagnosed with coronavirus within our system, you can actually sign up for a home-monitoring program where you will be mailed such tools as the oximeter that you’re talking about and a thermometer. But the difference is, you’re guided by a healthcare professional either over the phone or through your computer as to what to do, what not to do, questions you can ask if things aren’t working. I love how engaged people are in their health, and I love how thoughtful people are. But I do think we need to do it in a way that’s measured and has the expertise of the people that have been trained to support us.

Dryden: It seems to me that there were a few countries in the southern hemisphere that during their winter reported rather light flu seasons in 2020. The assumption being that because people were isolating due to COVID, they also were protecting themselves from other viruses that they might pick up just being around other people. And I wonder if there’s a potential silver lining that if we’re protecting ourselves from COVID, and wearing masks, staying apart, working from home if possible, or whatever it is, if maybe we might get lucky this flu season. Is there any possibility of that?

Hlatshwayo Davis: If you are conscientious about using preventative strategies that protect against respiratory viruses in ways that we know, not only does it drive down the morbidity and mortality — so that getting sick and potentially dying from those illnesses — it definitely has a protective benefit. It would not be a surprise to me. I think we have an opportunity here to use what we’ve learned since March around coronavirus to protect ourselves and our loved ones. I will say, though, that cannot happen in isolation. When it comes to the flu, the vaccine is critical. And so, that has to happen.


Dryden: So if you haven’t gotten your flu shot yet, it’s important to get one. It’s also important to remain vigilant with masking, social distancing, and handwashing as COVID vaccines gradually become available. Until then, there are still openings for volunteers who want to take part in vaccine trials at Washington University School of Medicine. For more information, please consult the Division of Infectious Diseases’ clinical trials website or email Again, that’s Show Me the Science is a production of the Office of Medical Public Affairs at Washington University School of Medicine in St. Louis. The goal of this project is to keep you informed and maybe teach you some things that will give you hope. Thanks for tuning in. I’m Jim Dryden. Stay safe.

Washington University School of Medicine’s 1,500 faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is a leader in medical research, teaching and patient care, ranking among the top 10 medical schools in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.

Jim retired from WashU Medicine Marketing & Communications in 2023. While at WashU Medicine, Jim covered psychiatry and neuroscience, pain and opioid research, orthopedics, diabetes, obesity, nutrition and aging. He formerly worked at KWMU (now St. Louis Public Radio) as a reporter and anchor, and his stories from the Midwest also were broadcast on NPR. Jim hosted the School of Medicine's Show Me the Science podcast, which highlights the outstanding research, education and clinical care underway at the School of Medicine. He has a bachelor's degree in English literature from the University of Missouri-St. Louis.