As the Jonas Salk Chair for Vaccine Research and professor of microbiology and molecular genetics at the University of Pittsburgh, Paul Duprex has been leading the local effort to create candidate vaccines for COVID-19.
In March, he joined an international team of scientists in using the tried and true measles vaccine—a weakened form of the virus Duprex has been studying for decades—as the basis for a new candidate vaccine against SARS-CoV-2. Phase 1 testing began in August.
More recently, Duprex joined forces with the massive global vaccine maker Serum Institute of India, which already produces vaccines for two-thirds of the world’s children, to manufacture a similar measles-based SARS-CoV-2 candidate vaccine developed solely at Pitt.
On Oct. 15 from 10 to 11:30 a.m. ET, Duprex will sit on a panel with vaccine experts from March of Dimes, Johns Hopkins, CDC Foundation and Pitt for a discussion about the challenges that lay ahead. The event is free and open to the public. Attendees must register at the Wilson Center website.
UPMC science writer Erin Hare caught up with Duprex in the Center for Vaccine Research, where he serves as director.
How do the vaccines being developed for COVID-19 differ from the vaccines of the past?
Think of a telephone. A telephone is very different in the 1960s compared to the cell phone that you carry in your pocket today. So, just imagine the same analogy and apply that to vaccines.
We can make vaccines in new ways. The toolkit is enormously large now, compared to what it was way back when. That doesn't mean that we don't do the same types of vaccines that were made in the 1960s—yes, that's part of the portfolio of vaccines, but there are many more vaccines available.
For instance, we can genetically engineer viruses. We can make one virus look like another virus. Or, we can take bits of genetic material and not even introduce proteins, which are normally recognized by the immune system. We can introduce the RNA, which makes the protein, which then is recognized by the immune system.
That's just examples of new ways to think about new vaccines, 65 years on.
Are there any features of the SARS-CoV-2 virus that make it especially easy or especially difficult to vaccinate against?
One of the advantages is that we have studied coronaviruses for many years. So, we understand a bit about which parts of the coronavirus can be used to make a good immune response.
The other thing which is interesting about coronaviruses is they're really big viruses, and they have the ability to correct mistakes whenever they replicate, so any mutation gets fixed straight away. That's good for us because that means the virus doesn't change much the way some other viruses do.
Like, for example, influenza. Influenza mixes it up all the time. HIV mixes it up all the time. But because SARS-CoV-2 has this drive to keep itself the same, that means the likelihood of changing is less. Plus, the virus just has one genetic segment, so it's not like influenza. So, instead of shuffling a pack of cards—the genetic material of influenza—SARS-CoV-2 can just play around with one sequence.
So those are all good things for us.
Hard things for us? Well, it's a brand-new virus. So, we still have to understand this relatively young virus. We have to understand a lot more about the biology of it. And, of course, the world is working hard on understanding the biology of SARS-CoV-2.
The WHO lists 42 COVID-19 vaccine candidates in clinical trials right now and 151 more in preclinical development. Why do we need so many?
We need so many because the first vaccine may not always be the best vaccine. It may work, but it might not work as efficiently as some of the other ones, which just take a bit longer to bring through the pipeline of development.
So, it's the same as that old analogy: You shouldn't keep all of your eggs in one basket. It's good to have multiple baskets for your eggs. And it's pretty good to have multiple approaches to deal with a virus that's rather new. The other part of having multiple approaches is we just don't know how long the immune response will last. And therefore we can't assume too much until we have the data.
So, it's all driven by science. Science is creative. People are creative. People come up with many ways to get to the same end point, and that's why we need lots of different sorts of vaccines.
The whole world is waiting for a vaccine. What gives you hope that we will get there soon?
Well, I think one of the things that gives me hope is there are a lot of individuals working on the problem. The world is focused—the virology community, the immunology community and many other disciplines—are laser focused on solving this problem. People have developed vaccines in the past. So, that gives me hope. But also what we have to remember is vaccines are not easy.
The average time to make a vaccine is 10 and a half years. And if you think about HIV, it pulls that average way up, because 36 years after identifying that virus, we still don't have a vaccine. So therefore vaccines are hard, but vaccines have led to the eradication of infectious diseases, and vaccines have done so much for human health. They consistently deliver, they consistently live up to their expectations, and they have delivered so many people who otherwise would not be here because vaccines actually work.
So, what gives me hope? Vaccines work.
A recent Kaiser Family Foundation poll found that two-thirds of Americans are concerned that a vaccine for COVID-19 might be rushed to market before it's verified safe and effective. Do you think that's a valid concern?
First and foremost, I'm sympathetic to individuals who are trying their best to understand something which is familiar to scientists—the process of vaccine development—but very foreign to the general public. No vaccine has ever been developed under the microscope like these candidate vaccines for SARS-CoV-2.
We also get our news from many different sources. We have social media, we have regular media—we have this tsunami of information. And that's what makes it really hard for the public to weed through, because not all of that information is equivalent.
So, what's important is to get information from verified, validated, sound sources—to look at the evidence produced by science. And the evidence says that vaccines work. That does not mean that vaccines work perfectly. Sometimes the influenza vaccine's great, sometimes in one particular year, for whatever reason, it just doesn't work as well. But we don't undermine all the vaccines because we do not get to perfection.
And we do realize that there are side effects, adverse events that happen. And that's why it's really important as we do vaccine development, clinical trials in the here and now, that we use all of the standard approaches in phase 1, phase 2, phase 3 clinical trials, to understand any potential effects, whatever that could be. And we only license safe, efficacious and life-giving vaccines.
What you also have to remember is these companies do much more than make a coronavirus vaccine. Some of them have made vaccines for many years. Some of them have never made a vaccine at all. So, there's an example of why I could be sympathetic and understand the population looking at it and thinking we're going to license something that has never been used before. But remember that these companies have reputations, they have other products, they have history, they have a brand, they are known and it's very unlikely a private company will throw all of that reputation in the air just to be first with unsafe, untested, non-satisfactory coronavirus vaccine.
Vaccines are not just produced and marketed and sold without a lot of care and a lot of attention to how they are made, tested and licensed.
This interview has been edited for length and clarity.