South Korean school students wear face masks during a special class on MERS virus at an elementary school in Seoul on June 3, 2015. South Korea on June 2 reported its first deaths from an outbreak of the MERS virus that has infected 25 people, caused widespread alarm and triggered a closer watch by Asian neighbours on Korean arrivals.  AFP PHOTO / JUNG YEON-JE        (Photo credit should read JUNG YEON-JE/AFP/Getty Images)