Question

Why polio vaccine is usually given orally and not injected?

Answer 1

1. Oral polio vaccine (OPV) is a live-attenuated vaccine, produced by the passage of the virus through non-human cells at a sub-physiological temperature, which produces spontaneous mutations in the viral genome.

2. As when it is administered orally it passes through the intestine and it make that region immune against the virus and prevents reinfection.