The United Nations has launched a massive vaccination drive in Rohingya refugee camps in Bangladesh amid fears of a cholera outbreak. The World Health Organisation warned last month of a growing cholera risk in the makeshift refugee camps in Bangladesh where more than 435,000 Rohingya Muslims have sought shelter from unrest in Myanmar. The UN refugee agency says it is on full alert for a new escalation in the Myanmar crisis after more than 11,000 Rohingya Muslims crossed the border into Bangladesh on Monday.