This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Live vaccines are 
Select and explain. 
A. TT, B. BCG, C. DPT, D. OPV
B: BCG
Answer: B: BCG 
Explanation: BCG consists of living bacteria derived from an attenuated bovine strain of tubercle bacilli. The bacilli used for vaccine production are descendants of the original Calmette strain of BCG (refer pgno:196 park 23rd edition)