Researchers Working To Speed Development Of A Zika Vaccine

The more that doctors and public health officials learn about Zika, the scarier it gets, they say. That means the pressure keeps mounting on researchers who are working to come up with a vaccine for the virus and get it out to the public.

Here & Now's Robin Young talks with Danny Vellom, senior director of end-to-end innovation at Sanofi Pasteur, which has a global team working on a Zika vaccine. They discuss the process of vaccine development, and when a Zika vaccine might be ready for the general public.

How close are we to having a vaccine?

“I have to take Anthony Fauci’s estimate as probably where everybody is, which is to say that we hope to have something ready for the general population in 2018.”

What is the difference between a DNA vaccine and what you are producing?

“My company, Sanofi Pasteur, is developing live attenuated vaccine, which is to say we are generating, through molecular genetics, a version of Zika that is still immunological, but doesn’t have the virulence, or doesn’t cause the disease. It’s a Zika virus that we have tweaked so that it doesn’t cause disease.”

How are you developing the vaccine?

“The original vaccine in this family was for yellow fever, and it was developed a long time ago. Since then, we have learned through molecular genetics how similar these viruses are in their genome and learned to swap genes and mutate genes, such that we can essentially build a nonvirulent virus, and still replicates in the body just like the disease virus, but it doesn’t cause the disease. So dengue is one version of that. Before that we had Japanese encephalitis vaccine and we’ve even developed, through clinical trials at least, a West Nile vaccine.”

What do we know about Zika?

“We are on a very steep learning curve. Birth defects are the first thing we see, we’re also starting to see more and more of the neurological effects, not in pregnant women, but in other parts of the population. Guillain-Barre syndrome has been widely reported. We’re starting to see other neurological sequelae that are related to the fact that it is an encephalitis. It prefers to end up in neurological tissue, in the brain and the spinal cord and people can have other symptoms that don’t really make the headlines but can really impact them, in a lot of cases, for the rest of their lives.”

Are drug companies competing to develop this vaccine?

“We’re competing to be the first to somehow impact this unmet medical need. When there’s something like this, where it’s truly impactful to a naïve population, much like what happened with Ebola last year, we’re all competing to get something out that can impact people's lives. There’s not a profit motive because we’re really looking to provide the vaccine to governments, to non-governmental agencies. Funding will probably come from all over, from Path and from Gates and from government to make surer that everybody gets it.”

So there’s no motivation to make a profit?

“No, it doesn’t work that way. Vaccines are rarely marketed or promoted in that way.”

When do you think you might start the human trials for Zika?

“We’re projecting that it will be in the first half of 2017. It takes some time to generate the vaccine candidates, to test them in animals, and then once we have the good animal data that says this is the candidate that we want to move forward with or maybe we move forward with two, then we begin the process of trying to build a manufacturing process for making it. It then goes through another round of animal testing, and with that body of data we’ve made it how it’s been manufactured and how it’s been tested, we can now go to the regulatory agency and say we’d like to run a human trial.”

Are you concerned that Zika may get worse?

“Absolutely. The two mosquitoes, unfortunately, are ubiquitous. They are in 30 states in the U.S., Mexico, Central America and South America. Climate and weather make a difference, but these are funny mosquitoes, they like to live in cities. They can live in an old tire that has a cup of dirty water in it and that’s awfully hard to deal with.”