Bangladesh today launched a massive drive to vaccinate Rohingya children against diphtheria after a suspected outbreak killed nine refugees and infected more than 700. <br/><br/>Health workers in Bangladesh said they had been caught unaware by the outbreak of the bacterial disease in the Rohingya refugee camps of southeast Bangladesh. <br/><br/>More than six lakh Rohingya are based in these camps, having fled violence in Myanmar in recent months. Bangladesh's health services department said of the 700 refugees infected, 104 most of them children – had contracted the disease in the last 24 hours. <br/><br/>The government and UN agencies are now vaccinating around two lakh fifty thousand children under the age of seven living in camps and temporary settlements near the border with Myanmar. <br/><br/>Diphtheria is a highly contagious respiratory disease that can be fatal if left untreated, but has become increasingly rare in recent decades due to high rates of vaccination.