Oral Active immunisation against cholera Child: For primary vaccination schedule: Given as a suspension (in doses of 3 ml, mixed with sodium hydrogen carbonate solution): 2-6 yr: 3 doses, at wkly intervals; >6 yr: 2 doses, at wkly intervals. Complete immunisation 1 wk prior to potential exposure. If >6 wk have elapsed between doses, primary immunisation course should be re-initiated. A single booster dose may be given after 6 mth (2-6 yr) or 2 yr (>6 yr), depending on the age of the patient to maintain protection.