This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
All are false regarding polio virus except: 
Select and explain. 
A. Most cases are symptomatic, B. Inactivated vaccine given IM, C. Inactivated polio vaccines are given to child less than 3 years of age, D. Only one type exists
B: Inactivated vaccine given IM
Answer: B: Inactivated vaccine given IM 
Explanation: Ans. (b) Inactivated vaccine is given IM Inactivated poliovaccine or IPV (salk type) is given subcutaneously or IM. Other options Option L. Most cases of polio are asymptomatic Option c Dose schedule of IPV: First dose when infant is 6 weeks old Additional doses are recommended prior to school entry and then every five years until the age of 18. Option d These are three serotypes of polio virus Most outbreaks of paralytic polio are due to type 1.