Using data from travelers to 4 countries in the Middle East, we estimated 3,250 (95% CI 1,300-6,600) severe cases of Middle East respiratory syndrome occurred in this region during September 2012-January 2016. This number is 2.3-fold higher than the number of laboratory-confirmed cases recorded in these countries.
Keywords: MERS-CoV; Middle East; Middle East respiratory syndrome; South Korea; coronavirus; disease outbreaks; incidence; population surveillance; respiratory infections; travel; viruses; zoonoses.