<prompt> Oral cholera vaccine is effective for: September 20056 months12 months2 years3 years  <response>: Ans. D: 3 years Oral vaccine is effective for at least 3 years. Injectable vaccine is effective for 3-6 months and protective value is about 50. Proguanil and antibiotics should be avoided from one week before and one week after the administration of the live oral attenuated vaccine 