This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Spleen, Subject name: Surgery
In which case pneumococcal vaccine is most effective: 
Select and explain. 
A. When given preoperatively, B. When given post operatively, C. Against all strains of bacteria, D. Against gram negative bacteria
A: When given preoperatively
Answer: A: When given preoperatively 
Explanation: Ans is 'a' ie When given preoperatively "Timing of vaccination generally is accepted as a minimum of 2 weeks before planned elective splenectomy and within 7 to 10 days after unplanned or emergent splenectomy, although data supporting this practice are lacking." -- Schwartz 9/e "Pneumococcal vaccine should be administered to all patients 2 weeks before elective splenectomy. Harrison 17/eIf the spleen is removed in emergency (eg. following trauma), vaccination should be given as soon as possible following surgery.Booster injection of pneumococcal vaccine should be given every 5 to 6 years.Other vaccines advisable in splenectomy pts: vaccines to Neisseria meningitides, Haemophilus influenza type b