The characteristics of polio vaccine are all except -
High-Yield Explanation
Park&;s Textbook of Preventive and Social Medicine 23rd edition Page no: 206, 207 After 3 doses of OPV, the mean propoion of infants with detectable serum neutralizing antibody level was only 73% for type1, 90% for type 2 and 70% for type 3 polio virus