Ask the Expert
with Dan Barouch, M.D., Ph.D., Director of the Center for Virology and Vaccine Research
Q: All the news about the Zika virus is very frightening, particularly because it initially spread so fast. Is there hope for a Zika vaccine in the future?
I have much hope. My team and I have shown that Zika vaccines work in animal studies, and clinical trials are currently underway. We are optimistic that finding a vaccine for Zika is possible.
For more than 12 years, my research team at Beth Israel Deaconess Medical Center has focused on developing and testing a novel vaccine for HIV. Our interest in Zika began in January 2016, when we saw headlines about the virus’s explosive spread in the Americas and its devastating consequences in pregnant women and infants, including microcephaly and congenital and neurological abnormalities.
It was immediately clear to us that a vaccine would be needed as a key global health countermeasure. Additionally, we reasoned that the development of a vaccine was a tractable target—which means it will likely be successful—for several reasons. First, Zika virus has much less variability than HIV: each virus particle is nearly identical genetically. Additionally, there is clear evidence of natural protective immunity in humans, as most adults infected with Zika make a full recovery.
We tested three different vaccines in mice and subsequently in monkeys, and each one provided 100 percent protection against Zika. The results were astonishing, particularly given that this was a virus that had never been studied before. We worked extremely rapidly: it took our team four months to establish the proof-of-concept in mice, six months to establish our proof-of-concept in monkeys, and ten months to begin our first clinical trial in humans. Our findings in animals were significant, as they were the very first demonstrations of Zika vaccine efficacy in the field. And not only were we able to test candidate vaccines, we also learned the levels of antibodies needed for protection.
We could never have made these rapid advances with Zika without the laboratory infrastructure and knowledge we had from our HIV work. It’s a very different virus than HIV, but the vaccine technology is similar. In my lab, we have experts in all the different areas required to produce and study vaccine candidates. The other element that was essential to our success in developing and testing Zika vaccines was philanthropy. When we started our work on Zika, we had no funding for this project—because the timeline to obtain federal grants is so long—so we relied on flexible philanthropic support for our pre-clinical studies. Those funds were invaluable to our efforts.
Today, we are conducting one of three first-in-human studies evaluating a Zika inactivated virus vaccine. We started the clinical trial in November 2016, ten months after we started our Zika work. The purified, inactivated virus vaccine that we are testing—the same type of vaccine as a flu shot—is promising because it’s a well-established type of vaccine for this type of virus and it’s known to be potent. The Clinical Principal Investigator is Dr. Kathryn Stephenson and the trial is being conducted here at the BIDMC Center for Virology and Vaccine Research. The Walter Reed Army Institute of Research is funding the study.
When we ask our study participants why they chose to take part in the trial, they often say that they want to do something to help combat the Zika epidemic. Our objective is to tackle critical global health problems and to make a lasting impact on human health. And our data with Zika vaccines give us great optimism that the development of a safe and effective Zika vaccine for humans will likely be possible.