Why are the vaccination rounds timed 4-8 weeks apart?
The reason that vaccination rounds are timed 4-8 weeks apart is to try and suppress the circulation of Polio virus from child to child in the community. The vaccine strain of the virus, when given to all of the children in a community, will actually replace the disease causing strains of polio virus thereby reducing the risk for the whole community. Spacing the rounds 4-8 weeks gives time for the disease causing strains to die out in the area.
