why 3 doses are given for polio why not just 1 dose?

why 3 doses are given for polio why not just 1 dose?
Polio Vaccination is given to babies at tenderstage. In vaccination they use exceedingly minute quantity of same virus. As the degree is very small, the babe-in-arms starts developing immunity. As this polio vaccine is offered at tender age it is not protected to offer the full dosage contained by dose. Hence they offer at three stages.
Your body have to build up an immunity by creating antibodies.
It is basically like Hepititis B shots. You hold to have a series of 3 or it is not effectual. Your body does not build up enough antibodies to be affective against that disease.
One dose is not sufficient to furnish permanent imperviousness. Repeat doses cause increased antibody production by 'memory' response. In endemic areas, 3 doses are not adequate. Now, they feel that 10 to 14 doses are required for complete protection. Hence, they hold Polio Days when all children beneath the age of 5 years are given polio vaccine.
Even three doses does not have 100 percent seroconversion or contained by common man's lexis do not offer 100 percent protection what to read out of single dose. Second and third doses act as booster over the first dose.