Despite the World Health Organization declaring Zika a public health emergency earlier this year, only one major pharmaceutical company is actively working on a vaccine.
According to a Bloomberg report, drug companies are taking a wait-and-see approach to the virus, because they don't think it's a priority.
Their worry? That humans will develop a natural resistance to the virus before a vaccine is ready for market.
Bloomberg quoted market analysis firm BMI Research about the status of the virus, "while Zika has a high potential impact on women of reproductive age, its limited effect on general health could easily see funding wane, particularly if Ebola saw resurgence or another pandemic threatened."
Sanofi is the only major drug company working on a vaccine.
“We have scientists, clinicians, toxicologists, epidemiologists that understand this family of viruses,” Nicholas Jackson, who heads the Zika vaccine project for Sanofi, told Bloomberg. “This gives us a great opportunity to move quickly, and quick is needed here.”