Paralytic polio is a serious form of poliomyelitis, an infection caused by the poliovirus. Because paralytic polio is so severe, it has historically occupied a large share of the media coverage of polio, and some very notable historical figures have suffered from paralytic polio, such as American President Franklin Delano Roosevelt. Occurrence of this form of polio is actually quite rare, and it is steadily decreasing.

The poliovirus prefers the environment of the intestinal tract, and it is also highly infectious. Someone infected with the disease usually suffers from a mild form which will often resolve on its own, with around 95% of poliomyelitis cases being classified as mild. In a few instances, however, the poliovirus will be more aggressive, and in around 2% of cases, it develops into paralytic polio.

In paralytic polio, the virus attacks the central nervous system. When only the spinal cord is affected, as in the vast majority of paralytic polio cases, it is known as spinal polio. When the brain stem is attacked, it is known as bulbar polio, and when both brain and spinal cord are involved, it is classified as bulbospinal polio. As the virus attacks the central nervous system, it causes paralysis and a host of complications.

The symptoms of paralytic polio include: difficulty swallowing, trouble breathing, muscle aches, fever, stiffness, muscle weakness, tremors, and spasms. In some cases, the muscles which regulate respiration become paralyzed, in which case the patient needs to be put on an artificial ventilator so that he or she can breathe. Historically, paralytic polio patients often wound up in iron lungs, specialized negative pressure ventilators.

In five to 10 percent of cases, paralytic polio kills. The mortality rate is higher in adults, in whom polio infections appear to be more severe. Many people suffer complications from paralytic polio, such as paralysis, malformed limbs, muscle weakness, and difficulty breathing. Physical therapy can greatly assist with these complications of the disease, making life more comfortable and enjoyable for the patient.

The great tragedy of paralytic polio is that is preventable through vaccination. In most regions of the world, herd immunity has been achieved through extensive vaccine coverage, making paralytic polio very rare. However, some developing nations still have instances of polio, much to the frustration of health care workers who would like to eradicate this disease.