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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Duration of immunity after typhoid vaccination is for -
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The correct answer is  <p>Vi polysaccharide vaccine:- Composed of purified Vi capsular polysaccharide from Ty2 S. Administration- subcutaneous/ intramuscularly. Age group more than 2 years. Only one dose required. Confers protection 7 days after injection. Efficacy-85% Duration of immunity-3yrs. To maintain protection,revaccination recommended every 3 years. {Reference: park&;s textbook of preventive and social medicine, 23rd edition, pg no.237}</p>