Sanofi’s announcement marked the most decisive commitment so far to developing a vaccine for the Zika virus, which is thought to be linked to microcephaly, a brain deformation that has affected nearly 4,000 newborns in Brazil, as well as a neurological disorder called Guillain-Barré syndrome.
Sanofi Pasteur, the company’s division dealing with vaccines, believes it has an advantage due to its experience developing vaccines for similar viruses, including yellow fever, Japanese encephalitis and dengue.
“We’ve got a big jump start here,” says Dr Nicholas Jackson, head of research with Sanofi Pasteur. “We have people in house, technology in house, ongoing surveillance in countries, a global network of collaborators and scientists and clinicians, so that gives us a big head start in finding the right technologies to tackle this significant emergency that the WHO has declared.”
Too early to establish a timeline
Vaccines typically take 10 years or more to be developed and, even if Sanofi believes its knowledge and networks give it a head start, it admits it is too early to determine how long development would take.
Professionals observing the outbreak have also warned against expecting a quick outcome.
“There really wasn’t much vaccine development going on for the Zika virus before this outbreak, as it wasn’t considered a public health threat,” says Amesh Adalja, an infectious diseases physician at Pittsburgh University. “The process can take years before a vaccine enters clinical trials.”
The WHO gave a new sense of urgency to the outbreak on Tuesday, warning the Zika virus could spread from Latin America, where it expects to see up to four million cases this year, to Africa and Asia.
But the UN agency is taking pains to stress the exact link between Zika and microcephaly is not yet known, although Anthony Costello, WHO director for maternal, child and adolescent health, says experts “believe the association is guilty until proven innocent”.
Understanding Zika’s link to microcephaly
“The emergency is on microcephaly and the neurological defects to try to better understand what the occurrence of these is in countries where Zika is occurring,” says David Heymann, chair of the WHO emergency committee on the microcephaly outbreak.
Heymann welcomes any efforts to develop a vaccine while also stressing the link with microcephaly is not yet established.
“I would think that companies would want to wait before this link is definitely established because, on its own, Zika virus appears less able to cause disease in humans than the chikungunya or the dengue virus,” Heymann says. “Before investing in a vaccine, it would be important to understand what the real link is with these birth defects.”
Sanofi says it can make much headway gathering and testing samples of the virus and building vaccine constructs as it works with other researchers and officials to understand Zika’s link with the microcephaly cases.
“We and others can investigate this association with these clinical complications in parallel, so that we don’t waste time while that investigation is ongoing,” Jackson says. “A number of people are already out there trying to look very carefully of the association and we should get a clearer picture in the coming months and years.”