On May 15, 2015, Zika virus circulation was confirmed in Brazil, and the Centers for Disease Control and Prevention (CDC) subsequently activated its Emergency Operations Center and responded to the Zika virus outbreak in the Americas and U.S. Territories. Between May 15 and December 15, 2016, a total of 707,133 autochthonous Zika virus cases were reported in the Region of the Americas.

Because of ongoing Zika virus transmission, the occurrence of associated complications, and the risk for recurrence of large outbreaks, countries where Aedes mosquitoes were present should continue surveillance for Zika virus disease, GBS, and congenital abnormalities.