The Brazilian president's chief of staff says it will take researchers between three and five years to develop a vaccine against the Zika virus.
Jaques Wagner told reporters Monday that Brazilian researchers are working with researchers in the United States. In his words: "If we are really lucky, it could be three years. But it could be between three and five years."
Wagner made the estimate just hours after the World Health Organisation declared the spread of Zika an international emergency.
It was in line with previous estimates by health officials working to combat the spread of the virus.