The Latest On Vaccine Development For The Coronavirus Disease

Aug 12, 2020

Yesterday Russian President Vladimir Putin said his country has developed a vaccine that works against the coronavirus disease. But many scientists say there’s a long way to go with testing and research before it’s proved safe and effective. Scientists worldwide are trying out more than 150 potential vaccines to learn the best way to stimulate the body’s immune response to COVID-19. One of them is Todd French, the head of Northern Arizona University’s new COVID-19 Testing Service Center. KNAU’s Melissa Sevigny spoke with him about the latest developments in the global push to end the pandemic.

Todd French
Credit Ken Ng/CTSC

So many of us are probably familiar with the flu vaccine which is a killed part of the flu virus and that stimulates an immune response. But there’s actually a lot of others ways you can create a vaccine.

Right. Clearly we have effective vaccines out there.… All of those are a mix of things. You have “attenuated viruses” in some like measles, mumps, rubella, and then you have “subunit vaccines,” diphtheria, pertussis, and they all seem to be effective. They last for years, because a) they stimulate good antibody responses, and then they stimulate lasting T cell responses. All good vaccines do both. We are just now starting to understand how important the T cell response is, in creating a long lasting vaccine. And COVID is teaching us a lot, unfortunately.

Tell me what a T cell is?

A T cell is a type of white blood cell. The killer T cells are directed by helper T cells to go and kill virus infected cells.

Do you have a sense of, among all of these different approaches, what seems to be the most promising so far?

So far the adenovirus-based vaccine platforms seemed to be gaining the most headway. It’s just a time will tell, type of thing.

And the adenovirus approach is where you’re using a different virus to generate parts of the coronavirus and that stimulates the immune response, did I have that right?

That’s correct, and being a live virus—live viruses are especially good at inducing T cell responses. It’s a more robust mechanism of immune activation.  

Let’s say everything works out with the science and we come up with a working vaccine for the coronavirus. What’s the timeline for getting that vaccine and rolling it out to the public?

That’s a very good question. It’s not only when will the vaccine will be available, it’s how good will it be? I believe they’ll consider a vaccine that is 50 percent protective, in other words, it protects 50 percent of the people that are vaccinated from an infection. I believe they’ll consider than to be a home run…and it needs to be relatively free of side effects. The front contenders right now are the mRNA/DNA vaccines, and the adenovirus vaccine. They’re in Phase 3 now, which means they’re being tried on thousands of people. They should be ready by the first quarter of next year I believe, if all things go reasonably well. Not everything is going to go perfectly well. But then it’s a matter of gearing up the production pipeline to produce hundreds of millions of doses. We may have vaccine companies competing for glass vials, for instance. We may run into logjams like that.

That minimum level set by the FDA for an effective vaccine, 50 percent, that seems rather low. If we have a vaccine that works half of the time, is that enough to control the pandemic?

No. It won’t be…. Fifty percent is not going to get us to herd immunity, coupled with the fact that probably 25-30 percent of the United States population is going to refuse to take any kind of vaccine. You’re left with a little bit of a conundrum, I think. I’m really optimistic that these better platforms, especially the adenovirus platform, will probably achieve much higher levels of protection than that.

Todd French, thank you so much for speaking with me.

Thank you.