Experts share info in scramble to fight 'impressive' Zika virus

The spread of Zika.

In a frantic effort against the Zika outbreak--which has now reportedly spread in more than 50 countries and territories--world vaccines experts are pooling knowledge to hopefully inform vaccine development.

At the World Vaccines Congress, leaders from the FDA, BARDA, Sabin Vaccine Institute, Sanofi Pasteur and Hawaii Biotech raised key questions associated with the Zika virus and discussed the challenges in creating a vaccine. Among the questions raised, Sabin Vaccine President Dr. Peter Hotez said it's important to determine whether rates of microcephaly are 1 in 100, as past Lancet data on an outbreak in French Polynesia have shown, or 1 in 3 as Brazilian experts are now suggesting.

Hotez went on to say that as with Ebola, the outbreak demonstrates that the scientific model for peer reviewing and publishing papers is outdated and in need of an overhaul because it takes too long to get information published in the face of fast-moving outbreaks.

"It's a wake up call that we need to change how we think about publishing papers," Hotez said.

At the talk, Wellington Sun, director of the FDA's division of vaccines and related product applications, questioned whether people who are infected have lifelong immunity, a factor that isn't yet known, he said.

On the subject of potential human challenge trials for a vaccine candidate, Sun, expressing his views and not necessarily the FDA's, said the "viability of a human challenge model is a very complex question, depending on good characterization of risk."

"We're talking about giving a pathogenic organism to consenting adults in, I think, an informed consent process. There has to be some level of certainty of what kind of risk that person would be facing in order to participate in the study. That said, I think it's not simply a regulatory question," suggesting that the issue could be debated by institutional review boards.

Just returned from a trip to Brazil, Sanofi Pasteur head of research Nicholas Jackson said there is "particularly disturbing" evidence that children can be born without microcephaly and then later have clinical neurological complications.

The experts at the panel also questioned whether scientists have done sufficient modeling to understand the natural history of the epidemic and where it might spread next.

As vaccine development progresses, Hotez, who called the virus "impressive" because of its noted challenges, said he anticipates a "big bottleneck" with regulators when it comes to testing Zika vaccines in pregnant women. "I would imagine that's about the highest bar there is in terms of a regulatory hurdle through the FDA," he said. "I just don't know how you can navigate that and negotiate it quickly."

At WHO's last count, 18 companies and organizations were working on vaccines, while the agency has said the NIH and India's Bharat Biotech are the farthest along. Inovio ($INO) has reported promise for its candidate, as well, hoping to move into Phase I by the end of the year.

Late last week, WHO reported that scientists have reached the consensus that the virus causes microcephaly--babies born with unusually small heads--and the neurological disorder Guillain-Barré syndrome.