The film The Final Inch depicts the problems still occurring fifty years after the development of the polio vaccine. It describes areas and Countries where the polio virus is still found around the World. 
 
Without vaccinations it could re-emerge and re-infect regions where it was eradicated decades ago. The film also notes that the first line of defense is a dedicated and continuous effort by international health workers going door-to-door to ensure every child is vaccinated.
 
Obstacles to eradication include lack of awareness, the large number of children requiring vaccination, geographical dispersal of the populations, social mores, religious beliefs, and suspicion of domestic and foreign governments.