
Zika virus is the first virus known to be transmitted to humans through the bite of an infected mosquito and through sex with an infected person. Over the course of 2016, the World Health Organization (WHO), along with the global research community, quickly built evidence that Zika virus transmission through sex was not only possible, but more common than previously assumed. But many questions still remain unanswered: How long does the virus stay in the body? Could the virus remain dormant in a person and reappear at a later stage? WHO is coordinating a research study in Brazil, called ZikaBra, to address these questions. The answers will help WHO sharpen its recommendations on how best to prevent Zika virus infection.













