The characteristics of polio vaccine are all except -: (A) Maintenance of cold chain, (B) 100% immunisation, (C) Killed vaccine is effective in India, (D) 5 doses of OPV given
Answer is B. 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