FDA Insight: Vaccines for COVID-19, Part 1
In Part 1 of FDA Insight’s vaccine series, Dr. Shah welcomes Dr. Peter Marks, director of FDA’s Center for Biologics Evaluation and Research, to discuss the basics of COVID-19 vaccine development.
FDA Insight: Episode 5 – Transcript
>> Anand Shah: Welcome back to another episode of FDA Insight. I'm Dr. Anand Shah, the Deputy Commissioner for Medical and Scientific Affairs here at the FDA. Thank you so much for joining us for our fifth episode. This week, we're going to do something a little different. We'll be discussing COVID-19 vaccines. But since there's so much to talk about, we're spreading it out over two episodes. My guest for these two episodes is Dr. Peter Marks, Director of FDA Center for Biologics Evaluation and Research, or CBER. Dr. Marks, welcome to FDA Insight.
>> Peter Marks: Thanks very much.
>> Anand Shah: For our audience, that doesn't have a medical background, tell us what a vaccine is and how they work.
>> Peter Marks: So, vaccines are products that stimulate a person's immune system to produce immunity to a specific disease and therefore protect the person from that disease. Vaccines are usually given through needle injections but can also be administered by mouth or sprayed into the nose. And by doing so, what they do is they cause the body's natural immune system to produce a response either through cells or through antibodies to help eliminate a disease from the body.
>> Anand Shah: So, why is a vaccine so important for COVID-19? I know that we're working on a number of therapies at the FDA and working together with industry to bring a therapy along. But why is a vaccine so important?
>> Peter Marks: Well, in the modern era when vaccines are available to address an infectious disease, they can, in some cases, help eliminate that vaccine (infectious disease) from the population, and at the very least, they can protect a large portion of the population against that infectious disease. Good examples of that have been smallpox, where the vaccine was so effective that we don't have smallpox anywhere around the world anymore. For COVID-19, the duty of a vaccine is that with a one or a few doses of a vaccine, people will be protected, hopefully for many, many months against the virus, and that will ultimately, if enough people are vaccinated, it will provide immunity in the population such that we'll be able to get back to normal lives together.
>> Anand Shah: Dr. Marks, how does your team at FDA help ensure the safety of a vaccine?
>> Peter Marks: So, FDA's role is twofold. We help product developers see the most straightforward and efficient way of developing their products so they can take them through the various steps that are needed to first design a product and then understand whether a product works in people. And then the other piece of what we do is we look at the data that a product developer gives to us, from the work they've done in animals and in people and the information they have about how they make the product, and we make sure that it meets our standards for safety and efficacy and product quality, so that at the end of the day, we know that when people are getting a vaccine, it's high quality and it's going to do what it is intended to do in a safe manner.
>> Anand Shah: So, Dr. Marks, even if a vaccine does what it's intended to do. Can a vaccine cause side effects?
>> Peter Marks: It's undeniable that any medical intervention tends to have some side effect or another. Vaccines, remarkably, have actually not that many side effects. And that's because we select to make sure that they don't because they're given to healthy people. And so it is possible that a vaccine could be associated with mild side effects. Anyone who's ever had a vaccine knows that you can have some soreness in your arm or perhaps redness in your arm. Occasionally, vaccines can be associated with a little fever after administration. But our job is to make sure that none of those are serious side effects. And we keep a watch out on the vaccines that are approved — that we approve — to make sure that we're not seeing any serious side effects. And if we do, we take action to make sure that we reduce or eliminate those serious side effects.
>> Anand Shah: So, what exactly does the FDA consider when evaluating a vaccine candidate?
>> Peter Marks: So, there are various aspects. First of all, let's start with we make sure that the product is made with high quality and that means that manufacturing standards are met. That's somewhat technical. So, I won't say a whole lot more about it. Then we make sure that the vaccine is safe. And unlike a medical product that's going to be used in someone who already has an illness, we're generally giving vaccines to people who are healthy. So any side effect is something we want to avoid. So, we will look in very large numbers of patients instead of the typical hundreds of patients that might be in a clinical trial for a drug meant to treat a disease, we tend to look in thousands of people before a vaccine is licensed to make sure that we don't see side effects. And even after a vaccine is licensed, we continue to look in literally millions of people to make sure we don't see side effects that become apparent because you treat enough people and then a very rare side effect becomes apparent.
And then in terms of efficacy, we look at the clinical trials that have been conducted and we ask that the clinical trials get conducted in a manner that makes it clear whether the vaccine does or does not do what it says it's going to do. In other words, does it protect against a disease or does it have -- show a sign of making an immune response that always correlates with being protective against the disease? And by looking at all those three things together, the quality, the safety, and the efficacy of the vaccine, we come together and decide that a vaccine meets our standards and can be licensed.
>> Anand Shah: Dr. Marks, let's talk about a specific example. We'll soon be entering what much of the public knows as flu season. Will a flu shot help protect patients against COVID-19?
>> Peter Marks: So not — the typical inactivated influenza vaccine that people get will not protect people against COVID-19, because the antibodies, the response that one gets and the immune response that one gets is directed against influenza. But I should be a little bit circumspect in how I answer this because it is possible that some live virus vaccines may help, kind of non-specifically stimulate the immune system. And people may read in the press about clinical trials of those vaccines that are going on.
I also should say something else that's really important. Even if that the influenza vaccine doesn't protect you against COVID-19, getting a flu shot this year in particular is really important because the less influenza like illness that we have to sort through in the middle of COVID-19, the easier it will be. Because at some point, if the COVID-19 outbreak continues into the late fall, we'll have both influenza and COIVD-19 and sorting through both will be challenging. The more people that are actually vaccinated against influenza, the easier it will be for doctors when they see a patient to know that it's more likely COVID-19 that they're seeing than influenza.
>> Anand Shah: Dr. Marks, so does taking a COVID-19 vaccine ensure that an individual won't get COVID-19? After all, can't people get the flu after getting the flu vaccine?
>> Peter Marks: So there — but let's break that up into a couple of things. First of all, the typical flu vaccine that's given, the inactivated flu vaccine, can't cause the flu. So you don't get the flu from getting the vaccine. But it is true that the flu vaccine on an average year, it only prevents flu in about half the people who get it. And yet that's very important because that means that it leads to half as many deaths related to influenza each year. So it's still a very important vaccine for people to get, even if it's not 100 percent effective. And it's possible that a COVID-19 vaccine won't be 100 percent effective because there really isn't such a thing as 100 percent effective vaccine.
There are vaccines that approach 100 percent efficacy; an example of one of those is the measles vaccine. But having some protection is better than none. And what we also know is that once one reaches a certain level of protection, roughly 70 percent, and if 70 percent of the population gets that vaccine, you start to get to a place where the infectious disease that you're trying to prevent, in this case, let's read COVID-19 into that, it doesn't have anywhere to go and you start to be able to help wipe that infectious disease out.
So one other thing I should mention, I think it's implied in your question is it's true that we don't know yet how long one will get protection from a single vaccine. That's what the clinical trials will tell us. It may be that people will have to be revaccinated at some point, but we don't know that. So we'll just have to see.
>> Anand Shah: We'll pause right there on this episode of FDA Insight. And next week, we'll keep discussing vaccines for COVID-19. Dr. Marks, thanks very much for sharing this very timely info. We're looking forward to talking to you again next week.
>> Peter Marks: Thank you so much for the great questions.
>> Anand Shah: I'd like to thank our audience for listening. As always, we'll be providing you insight in plain language to help you understand the products that we regulate, the issues that we face, and the processes that we follow.
We hope you enjoyed this episode of FDA Insight. Please subscribe on your favorite podcast app, such as Apple Podcasts, Google Play, and others. See you next week.
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