What should we take from Pfizer's promising COVID-19 vaccine news?

Approval by the U.S. Food and Drug Administration for the recently announced Pfizer COVID-19 vaccine could come within a matter of weeks, and some doses could be available before the end of the year, says Josh Sharfstein, vice dean for public health practice and community engagement at the Johns Hopkins Bloomberg School of Public Health.

The vaccine may not be widely available for everyone until the summer or fall of 2021, he cautions, but early indications related to the Pfizer vaccine are cause for optimism.

For more insights on the state of vaccine development in the U.S. and around the world, Sharfstein spoke with the Bloomberg School's Public Health On Call for a special bonus episode that explores the next steps for public health officials now that vaccine trials near their conclusions.

So today we want to talk about this week's really encouraging news from Pfizer about a vaccine. Can you tell us about the news?

Pfizer reported some of the results from its big vaccine study—I think there are something like 46,000 patients—and they found that the people in the group that got the vaccine were 90% less likely to get COVID-19 than the people who got the placebo. That's a really strong showing of effectiveness.

So where do we go from here? This is still early, right?

Well, the company said that it needed to collect a few more weeks of safety data and then it would bring that data, in the form of an application, to the Food and Drug Administration. From there, the Food and Drug Administration reviews the data and will convene an independent advisory committee to provide some input, and then make a decision on making it available to groups in the United States.

How long could this process take?

Probably it will be measured in weeks.

So we could have a vaccine made available by the end of the year?

Definitely. I think that's possible.

So if the data continued to look good, how does the FDA go about making the vaccine available?

The FDA has a few options. The traditional route is full licensure, otherwise known as approval. That's probably less likely in the short term because there are a number of steps associated with licensure and approval that take time and would probably take too long in this situation. The other options are emergency use authorization, which is a tool that the FDA has in a declared emergency like the pandemic to make medical products like vaccines available. It's also possible that the agency could use what's called an expanded access protocol, which basically considers it still investigational.

I think the choice that the FDA has, will depend in part on the strength of the evidence. I imagine that as the agency is looking at the data and as the advisory committee is looking at the data, they'll have a sense of whether they're ready to go for emergency use authorization or whether to have an interim step, which might be essentially a broad protocol for certain groups of people to have access to the vaccine.

Can you tell us a little bit about this vaccine? It's a little bit unusual it's made from RNA and there's not been a vaccine made with RNA before.

The typical vaccines are often a version of the virus, but weakened, like for example the inactivated polio vaccine. But this vaccine is just RNA, and the idea is the RNA gets into your own cells and makes the protein that teaches the immune system to recognize and eventually kill the virus when you're exposed to the real virus.

And is the idea that it would be more effective this way?

Well, it's a way to make a vaccine pretty quickly and hopefully it will be quite effective. I mean, that's what the early results show. Truthfully, there have not been approved vaccines with this technology, so we're just learning about how effective it is

From what I've read this. If this vaccine is approved and it's successful that we would see other diseases potentially in the future be a vaccinated against through an RNA vaccine.

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I think that's quite possible. I mean, I think this is very exciting. And one of the other aspects of it is very fast. I mean, usually vaccine development takes many years and they started working on this as soon as the genetic code of the virus was known, because essentially they figured out which protein to target and they made the RNA that corresponds to that protein.

So all the promises that this would come quickly are starting to come true.

It's pretty fast. You're right, they're starting to come true. And we just hope that everything proceeds like we would want.

And of course, this doesn't necessarily mean that this vaccine will be the vaccine. It's still early.

Well, you know, there are several other vaccines and studies, but I think this is a quite hopeful sign that this vaccine will make it through and become available to the public, initially for high-risk groups and potentially, eventually for everyone. It's also a really good sign because the other vaccines that are in late stage clinical trials are also targeting the same protein of the virus, in some cases in slightly different ways. But if targeting that protein causes a good set of immune protections for the individual, then that hopefully is very promising for the other vaccines as well.

So how might this work? My understanding is that we need several vaccines to be approved in order to have enough vaccine to vaccinate everybody. If we only have the Pfizer vaccine, that's not going to be enough. So will these other clinical trials continue so that we can find out if we have more than one vaccine?

Well, I mean, from the standpoint of humanity, we really need at least one really good vaccine and then we could all work to make it available to everybody as quick as we can. The hope, though, is that there will be more than one, because maybe the vaccine will work better in certain populations than others, and also for this issue of production. Each of the companies that are making vaccines is also developing an early effort to produce a number of doses. The more of those that are good vaccines, the faster we'll have more doses. So I think it's more a question of speed.

There are still questions about how this vaccine would be distributed. Do we know any more about those efforts, in terms of to whom they would be distributed?

There are a few different dimensions of the challenge of distribution. One of them is this vaccine has to be kept very, very cold during most of its passage through the distribution system because it's an RNA vaccine. But the issue you're raising is, who gets the vaccine? The process after the FDA decides to make it available, is that the Centers for Disease Control and Prevention convenes a committee that looks at the evidence about the vaccine, considers all kinds of different advice that it's gotten, including from the National Academies of Science, Engineering, and Medicine, and makes a plan for the highest risk groups to get vaccinated.

We expect that that plan will include health care workers, other essential employees, as well as people who are at very high risk for serious illness and death—people who are very old or have serious conditions that predispose them to a bad course of COVID-19. It'll depend on what the data show. For example, they're going to look at the data to see the response in older adults, and if that response is strong in older adults, then it is very likely that older adults will be some part of that high-risk group recommended.

You have any hints maybe about when this will become widely distributed, not necessarily this vaccine, but a vaccine?

Well, I think generally the timeline is enough vaccine for a lot of people in high risk groups by the beginning of 2021. And then it will be into 2021, maybe the summer or the fall, where there's really vaccine everywhere for everyone. That is the hope. If all of these trials prove that the vaccines are ready.

Are you more optimistic today than you were two weeks ago?

Oh yeah, absolutely. We know a vaccine can help people get antibodies. And on that basis, some countries started to make vaccines available just on the basis of antibodies. But in the United States, we said we want to make sure that it's actually effective in protecting people from COVID-19. And that's what this study appears to show. So that that's a big step. It's not every step, but it's a big step.

We've had huge increases the number of cases in the last week. We're seeing over 100,000 new cases a day, over 120,000 new cases a day. And I'm wondering if that's somewhat helpful when you're developing a vaccine when there's more of the disease around?

I think the main issue there is that it's a very serious situation with the coronavirus in the United States right now. Not only are cases going up, but hospitalizations are going up, deaths are going up. In some places there's not enough room in the hospital for patients and they're building extra hospitals. And we really, as a country, need to come together and recommit ourselves to keeping vigilant against the virus and saving as many lives as possible.

The idea of a vaccine, it's kind of like the light at the end of the tunnel. It's the idea that we're not stuck in this situation forever. If we can come together, if we can wear masks, if we can distance and wash our hands and do the things we need to do, then we deny the chance for the virus to kill a lot of people while we're setting up for a vaccine, which really provides a way, over time, to end the pandemic.

Because it's gotten really scary.

It's a very serious situation. And I know that there are a lot of people who are quite worried, understandably, that they're going to be at risk or their families are going to be at risk, and that's balanced against the fatigue people have about, "Oh, how long do I have to go around wearing a mask? And how long do I have to stay away from my friends and big indoor parties?" And the answer is a little while longer, but science is coming to the rescue here and we have to just give it time.

Talk to me about the global situation. China and Russia, I understand, have vaccines of some sort that they are distributing. What do we know about those vaccines and how might they compare it to this Pfizer vaccine?

I'm not aware that those vaccines have this kind of evidence—evidence of actually preventing disease. I think another aspect of the global situation is, how do we make sure that countries around the world have access to safe and effective vaccines as they become available? That's another issue that's going to be playing out over the next several months,I think.

How are those decisions made?

And that there's no one decision point. The countries are coming together to share vaccine with other countries. Companies are making commitments to make vaccine available to, for example, low-income countries, but it's hard to know exactly how it's all going to play out because we don't know which of the vaccines in development are going to be ready to go. But as that comes into focus, there will be opportunities to make sure that vaccines are able to be distributed around the world.

In a pandemic, it doesn't really make sense just for your own country to be protected. We've got to protect the United States. I mean, we have the worst outbreak, so if you distributed vaccine for the worst outbreak, the United States in many ways has the worst outbreak. But at the same time, just focusing on the United States, just having that as your entire frame of reference, we're not going to be safe as long as there are other countries in the world that have serious outbreaks. And so it's in all of our interests to defeat the virus.

#### Well Josh, thank you so much for your time.

Thanks for having me.

Public Health On Call is produced by Joshua Sharfstein, Lindsay Smith Rogers, Stephanie Desmon, and Lymari Morales. Audio production by Spencer Greer, Nial Owen McCusker, Cian Oatts, and Matthew Martin with support from Chip Hickey. Distribution by Nick Moran.