This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
True about Helicobacter pylori are all except: 
Select and explain. 
A. Urea, breath test is diagnostic, B. Gram negative, flagellated bacilli, C. Risk factor for development of adenocarcinoma of stomach, D. It provides life-long immunity
D: It provides life-long immunity
Answer: D: It provides life-long immunity 
Explanation: Ans. is 'd' i.e., It provides life-long immunity(Ref: Harrison, 17th/e, p. 946, 19th/e, p. 1038; Ananthanarayan, 9th/e, p. 400)Helicobacter pylori infection doesn't provide life-long immunity.