sentences:  The large-scale use of antibody serum to prevent and treat polio had a number of drawbacks, however, including the observation that the immunity provided by the serum did not last long, and the protection offered by the antibody was incomplete, that re-injection was required during each epidemic outbreak, and that the optimal time frame for administration was unknown.The antibody serum was widely administered, but obtaining the serum was an expensive and time-consuming process, and the focus of the medical community soon shifted to the development of a polio vaccine.Early management practices for paralyzed muscles emphasized the need to rest the affected muscles and suggested that the application of splints would prevent tightening of muscle, tendons, ligaments, or skin that would prevent normal movement.