Kenya is set to begin a mass vaccination drive against cholera, which has killed 78 people since September and infected a total of 4,000. However public health experts are warning that if people do not have access to clean water and improved sanitation, there could be a rise in cases that could overwhelm hospitals. A total of one million vaccine doses are needed, says Kenya’s health chief, who warns that majority of patients seeking treatment in hospitals come when at a late stage, and some die as a result.