This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Preservative added in DPT vaccine is - 
Select and explain. 
A. Zinc phosphate, B. Aluminium phosphate, C. MgSO4, D. ZnSO4
B: Aluminium phosphate
Answer: B: Aluminium phosphate 
Explanation: Page 162 Park&;s textbook of Preventive and social medicine 23rd edition DPT vaccine provides immunity against diphtheria peussis and tetanus Peusis component in the DPT vaccine enhance the potency of diphtheria toxoid There are two types of DPT vaccine -plain and adsorbed Adsorption is usually carried out on a mineral carrier like aluminium phosphate or hydroxide Studies have shown that adsorption increases the immunological effectiveness of the vaccine The WHO recommend that only advent DPT preparation be utilised in immunization programmes